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A multi-core processor is a
microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...
on a single
integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
with two or more separate processing units, called cores, each of which reads and executes program instructions. The instructions are ordinary
CPU instructions In computer programming, machine code is any low-level programming language, consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Each instruction causes the CPU to perform a very ...
(such as add, move data, and branch) but the single processor can run instructions on separate cores at the same time, increasing overall speed for programs that support multithreading or other
parallel computing Parallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different f ...
techniques. Manufacturers typically integrate the cores onto a single integrated circuit
die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semicondu ...
(known as a chip multiprocessor or CMP) or onto multiple dies in a single
chip package Integrated circuits are put into protective packages to allow easy handling and assembly onto printed circuit boards and to protect the devices from damage. A very large number of different types of package exist. Some package types have stand ...
. The microprocessors currently used in almost all personal computers are multi-core. A multi-core processor implements
multiprocessing Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There ar ...
in a single physical package. Designers may couple cores in a multi-core device tightly or loosely. For example, cores may or may not share caches, and they may implement
message passing In computer science, message passing is a technique for invoking behavior (i.e., running a program) on a computer. The invoking program sends a message to a process (which may be an actor or object) and relies on that process and its supporting ...
or
shared-memory In computer science, shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies. Shared memory is an efficient means of passing data between prog ...
inter-core communication methods. Common
network topologies Network topology is the arrangement of the elements ( links, nodes, etc.) of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and contr ...
used to interconnect cores include
bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
, ring, two-dimensional
mesh A mesh is a barrier made of connected strands of metal, fiber, or other flexible or ductile materials. A mesh is similar to a web or a net in that it has many attached or woven strands. Types * A plastic mesh may be extruded, oriented, exp ...
, and
crossbar Crossbar may refer to: Structures * Latch (hardware), a post barring a door * Top tube of a bicycle frame * Crossbar, the horizontal member of various sports goals * Crossbar, a horizontal member of an electricity pylon Other * In electronic ...
. Homogeneous multi-core systems include only identical cores;
heterogeneous Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
multi-core systems have cores that are not identical (e.g. big.LITTLE have heterogeneous cores that share the same
instruction set In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ...
, while
AMD Accelerated Processing Unit AMD Accelerated Processing Unit (APU), formerly known as Fusion, is a series of 64-bit microprocessors from Advanced Micro Devices (AMD), combining a general-purpose AMD64 central processing unit (CPU) and integrated graphics processing un ...
s have cores that do not share the same instruction set). Just as with single-processor systems, cores in multi-core systems may implement architectures such as
VLIW Very long instruction word (VLIW) refers to instruction set architectures designed to exploit instruction level parallelism (ILP). Whereas conventional central processing units (CPU, processor) mostly allow programs to specify instructions to exe ...
,
superscalar A superscalar processor is a CPU that implements a form of parallelism called instruction-level parallelism within a single processor. In contrast to a scalar processor, which can execute at most one single instruction per clock cycle, a sup ...
,
vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...
, or multithreading. Multi-core processors are widely used across many application domains, including general-purpose, embedded,
network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematic ...
,
digital signal processing Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are ...
(DSP), and
graphics Graphics () are visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of data, as in design and manufacture, ...
(GPU). Core count goes up to even dozens, and for specialized chips over 10,000, and in
supercomputer A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructio ...
s (i.e. clusters of chips) the count can go over 10 million (and in one case up to 20 million processing elements total in addition to host processors). The improvement in performance gained by the use of a multi-core processor depends very much on the
software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consist ...
algorithms used and their implementation. In particular, possible gains are limited by the fraction of the software that can run in parallel simultaneously on multiple cores; this effect is described by Amdahl's law. In the best case, so-called
embarrassingly parallel In parallel computing, an embarrassingly parallel workload or problem (also called embarrassingly parallelizable, perfectly parallel, delightfully parallel or pleasingly parallel) is one where little or no effort is needed to separate the problem ...
problems may realize speedup factors near the number of cores, or even more if the problem is split up enough to fit within each core's cache(s), avoiding use of much slower main-system memory. Most applications, however, are not accelerated as much unless programmers invest effort in
refactoring In computer programming and software design, code refactoring is the process of restructuring existing computer code—changing the '' factoring''—without changing its external behavior. Refactoring is intended to improve the design, structu ...
. The parallelization of software is a significant ongoing topic of research. Cointegration of multiprocessor applications provides flexibility in network architecture design. Adaptability within parallel models is an additional feature of systems utilizing these protocols.


Terminology

The terms ''multi-core'' and ''dual-core'' most commonly refer to some sort of
central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, a ...
(CPU), but are sometimes also applied to
digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio s ...
s (DSP) and
system on a chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memor ...
(SoC). The terms are generally used only to refer to multi-core microprocessors that are manufactured on the ''same'' integrated circuit
die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semicondu ...
; separate microprocessor dies in the same package are generally referred to by another name, such as ''
multi-chip module A multi-chip module (MCM) is generically an electronic assembly (such as a package with a number of conductor terminals or "pins") where multiple integrated circuits (ICs or "chips"), semiconductor dies and/or other discrete components are in ...
''. This article uses the terms "multi-core" and "dual-core" for CPUs manufactured on the ''same'' integrated circuit, unless otherwise noted. In contrast to multi-core systems, the term ''multi-CPU'' refers to multiple physically separate processing-units (which often contain special circuitry to facilitate communication between each other). The terms ''many-core'' and ''massively multi-core'' are sometimes used to describe multi-core architectures with an especially high number of cores (tens to thousands). Some systems use many soft microprocessor cores placed on a single
FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware d ...
. Each "core" can be considered a "
semiconductor intellectual property core In electronic design, a semiconductor intellectual property core (SIP core), IP core, or IP block is a reusable unit of logic, cell, or integrated circuit layout design that is the intellectual property of one party. IP cores can be licensed t ...
" as well as a CPU core.


Development

While manufacturing technology improves, reducing the size of individual gates, physical limits of
semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way ...
-based
microelectronics Microelectronics is a subfield of electronics. As the name suggests, microelectronics relates to the study and manufacture (or microfabrication) of very small electronic designs and components. Usually, but not always, this means micrometre- ...
have become a major design concern. These physical limitations can cause significant heat dissipation and data synchronization problems. Various other methods are used to improve CPU performance. Some ''
instruction-level parallelism Instruction-level parallelism (ILP) is the parallel or simultaneous execution of a sequence of instructions in a computer program. More specifically ILP refers to the average number of instructions run per step of this parallel execution. Disc ...
'' (ILP) methods such as
superscalar A superscalar processor is a CPU that implements a form of parallelism called instruction-level parallelism within a single processor. In contrast to a scalar processor, which can execute at most one single instruction per clock cycle, a sup ...
pipelining are suitable for many applications, but are inefficient for others that contain difficult-to-predict code. Many applications are better suited to ''
thread-level parallelism Task parallelism (also known as function parallelism and control parallelism) is a form of parallelization of computer code across multiple processors in parallel computing environments. Task parallelism focuses on distributing tasks—concurren ...
'' (TLP) methods, and multiple independent CPUs are commonly used to increase a system's overall TLP. A combination of increased available space (due to refined manufacturing processes) and the demand for increased TLP led to the development of multi-core CPUs.


Commercial incentives

Several business motives drive the development of multi-core architectures. For decades, it was possible to improve performance of a CPU by shrinking the area of the integrated circuit (IC), which reduced the cost per device on the IC. Alternatively, for the same circuit area, more transistors could be used in the design, which increased functionality, especially for
complex instruction set computing A complex instruction set computer (CISC ) is a computer architecture in which single instructions can execute several low-level operations (such as a load from memory, an arithmetic operation, and a memory store) or are capable of multi-step o ...
(CISC) architectures.
Clock rate In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pr ...
s also increased by orders of magnitude in the decades of the late 20th century, from several megahertz in the 1980s to several gigahertz in the early 2000s. As the rate of clock speed improvements slowed, increased use of parallel computing in the form of multi-core processors has been pursued to improve overall processing performance. Multiple cores were used on the same CPU chip, which could then lead to better sales of CPU chips with two or more cores. For example, Intel has produced a 48-core processor for research in cloud computing; each core has an x86 architecture.


Technical factors

Since computer manufacturers have long implemented
symmetric multiprocessing Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all ...
(SMP) designs using discrete CPUs, the issues regarding implementing multi-core processor architecture and supporting it with software are well known. Additionally: * Using a proven processing-core design without architectural changes reduces design risk significantly. * For general-purpose processors, much of the motivation for multi-core processors comes from greatly diminished gains in processor performance from increasing the
operating frequency In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pr ...
. This is due to three primary factors: *# The ''memory wall''; the increasing gap between processor and memory speeds. This, in effect, pushes for cache sizes to be larger in order to mask the latency of memory. This helps only to the extent that memory bandwidth is not the bottleneck in performance. *# The ''ILP wall''; the increasing difficulty of finding enough parallelism in a single instruction stream to keep a high-performance single-core processor busy. *# The ''power wall''; the trend of consuming exponentially increasing power (and thus also generating exponentially increasing heat) with each factorial increase of operating frequency. This increase can be mitigated by " shrinking" the processor by using smaller traces for the same logic. The ''power wall'' poses manufacturing, system design and deployment problems that have not been justified in the face of the diminished gains in performance due to the ''memory wall'' and ''ILP wall''. In order to continue delivering regular performance improvements for general-purpose processors, manufacturers such as
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...
and AMD have turned to multi-core designs, sacrificing lower manufacturing-costs for higher performance in some applications and systems. Multi-core architectures are being developed, but so are the alternatives. An especially strong contender for established markets is the further integration of peripheral functions into the chip.


Advantages

The proximity of multiple CPU cores on the same die allows the
cache coherency In computer architecture, cache coherence is the uniformity of shared resource data that ends up stored in multiple local caches. When clients in a system maintain caches of a common memory resource, problems may arise with incoherent data, whi ...
circuitry to operate at a much higher clock rate than what is possible if the signals have to travel off-chip. Combining equivalent CPUs on a single die significantly improves the performance of cache snoop (alternative:
Bus snooping Bus snooping or bus sniffing is a scheme by which a coherency controller (snooper) in a cache (a snoopy cache) monitors or snoops the bus transactions, and its goal is to maintain a cache coherency in distributed shared memory systems. A cache cont ...
) operations. Put simply, this means that signals between different CPUs travel shorter distances, and therefore those signals
degrade Degradation may refer to: Science * Degradation (geology), lowering of a fluvial surface by erosion * Degradation (telecommunications), of an electronic signal * Biodegradation of organic substances by living organisms * Environmental degradatio ...
less. These higher-quality signals allow more data to be sent in a given time period, since individual signals can be shorter and do not need to be repeated as often. Assuming that the die can physically fit into the package, multi-core CPU designs require much less
printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...
(PCB) space than do multi-chip SMP designs. Also, a dual-core processor uses slightly less power than two coupled single-core processors, principally because of the decreased power required to drive signals external to the chip. Furthermore, the cores share some circuitry, like the L2 cache and the interface to the
front-side bus A front-side bus (FSB) is a computer communication interface (bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between the ...
(FSB). In terms of competing technologies for the available silicon die area, multi-core design can make use of proven CPU core library designs and produce a product with lower risk of design error than devising a new wider-core design. Also, adding more cache suffers from diminishing returns. Multi-core chips also allow higher performance at lower energy. This can be a big factor in mobile devices that operate on batteries. Since each core in a multi-core CPU is generally more energy-efficient, the chip becomes more efficient than having a single large monolithic core. This allows higher performance with less energy. A challenge in this, however, is the additional overhead of writing parallel code.


Disadvantages

Maximizing the usage of the computing resources provided by multi-core processors requires adjustments both to the
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
(OS) support and to existing application software. Also, the ability of multi-core processors to increase application performance depends on the use of multiple threads within applications. Integration of a multi-core chip can lower the chip production yields. They are also more difficult to manage thermally than lower-density single-core designs. Intel has partially countered this first problem by creating its quad-core designs by combining two dual-core ones on a single die with a unified cache, hence any two working dual-core dies can be used, as opposed to producing four cores on a single die and requiring all four to work to produce a quad-core CPU. From an architectural point of view, ultimately, single CPU designs may make better use of the silicon surface area than multiprocessing cores, so a development commitment to this architecture may carry the risk of obsolescence. Finally, raw processing power is not the only constraint on system performance. Two processing cores sharing the same system bus and memory bandwidth limits the real-world performance advantage. In a 2009 report, Dr Jun Ni showed that if a single core is close to being memory-bandwidth limited, then going to dual-core might give 30% to 70% improvement; if memory bandwidth is not a problem, then a 90% improvement can be expected; however, Amdahl's law makes this claim dubious. It would be possible for an application that used two CPUs to end up running faster on a single-core one if communication between the CPUs was the limiting factor, which would count as more than 100% improvement.


Hardware


Trends

The trend in processor development has been towards an ever-increasing number of cores, as processors with hundreds or even thousands of cores become theoretically possible. In addition, multi-core chips mixed with
simultaneous multithreading Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar CPUs with hardware multithreading. SMT permits multiple independent threads of execution to better use the resources provided by modern proces ...
, memory-on-chip, and special-purpose "heterogeneous" (or asymmetric) cores promise further performance and efficiency gains, especially in processing multimedia, recognition and networking applications. For example, a big.LITTLE core includes a high-performance core (called 'big') and a low-power core (called 'LITTLE'). There is also a trend towards improving energy-efficiency by focusing on performance-per-watt with advanced fine-grain or ultra fine-grain
power management Power management is a feature of some electrical appliances, especially copiers, computers, computer CPUs, computer GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power st ...
and dynamic
voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...
and frequency scaling (i.e.
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
computers and
portable media player A portable media player (PMP) (also including the related digital audio player (DAP)) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. The data is typically stored o ...
s). Chips designed from the outset for a large number of cores (rather than having evolved from single core designs) are sometimes referred to as
manycore Manycore processors are special kinds of multi-core processors designed for a high degree of parallel processing, containing numerous simpler, independent processor cores (from a few tens of cores to thousands or more). Manycore processors are u ...
designs, emphasising qualitative differences.


Architecture

The composition and balance of the cores in multi-core architecture show great variety. Some architectures use one core design repeated consistently ("homogeneous"), while others use a mixture of different cores, each optimized for a different, "
heterogeneous Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
" role. How multiple cores are implemented and integrated significantly affects both the developer's programming skills and the consumer's expectations of apps and interactivity versus the device. A device advertised as being octa-core will only have independent cores if advertised as ''True Octa-core'', or similar styling, as opposed to being merely two sets of quad-cores each with fixed clock speeds. The article "CPU designers debate multi-core future" by Rick Merritt, EE Times 2008, includes these comments:


Software effects

An outdated version of an anti-virus application may create a new thread for a scan process, while its
GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
thread waits for commands from the user (e.g. cancel the scan). In such cases, a multi-core architecture is of little benefit for the application itself due to the single thread doing all the heavy lifting and the inability to balance the work evenly across multiple cores. Programming truly multithreaded code often requires complex co-ordination of threads and can easily introduce subtle and difficult-to-find bugs due to the interweaving of processing on data shared between threads (see
thread-safety Thread safety is a computer programming concept applicable to multi-threaded code. Thread-safe code only manipulates shared data structures in a manner that ensures that all threads behave properly and fulfill their design specifications without un ...
). Consequently, such code is much more difficult to debug than single-threaded code when it breaks. There has been a perceived lack of motivation for writing consumer-level threaded applications because of the relative rarity of consumer-level demand for maximum use of computer hardware. Also, serial tasks like decoding the
entropy encoding In information theory, an entropy coding (or entropy encoding) is any lossless data compression method that attempts to approach the lower bound declared by Shannon's source coding theorem, which states that any lossless data compression method ...
algorithms used in
video codec A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, '' codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an ...
s are impossible to parallelize because each result generated is used to help create the next result of the entropy decoding algorithm. Given the increasing emphasis on multi-core chip design, stemming from the grave thermal and power consumption problems posed by any further significant increase in processor clock speeds, the extent to which software can be multithreaded to take advantage of these new chips is likely to be the single greatest constraint on computer performance in the future. If developers are unable to design software to fully exploit the resources provided by multiple cores, then they will ultimately reach an insurmountable performance ceiling. The telecommunications market had been one of the first that needed a new design of parallel datapath packet processing because there was a very quick adoption of these multiple-core processors for the datapath and the control plane. These MPUs are going to replace the traditional Network Processors that were based on proprietary
microcode In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a la ...
or
picocode In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a laye ...
.
Parallel programming Parallel computing is a type of computing, computation in which many calculations or Process (computing), processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. ...
techniques can benefit from multiple cores directly. Some existing
parallel programming model In computing, a parallel programming model is an abstraction of parallel computer architecture, with which it is convenient to express algorithms and their composition in programs. The value of a programming model can be judged on its ''generality ...
s such as
Cilk Plus Cilk, Cilk++, Cilk Plus and OpenCilk are general-purpose programming languages designed for multithreaded parallel computing. They are based on the C and C++ programming languages, which they extend with constructs to express parallel loo ...
,
OpenMP OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared-memory multiprocessing programming in C, C++, and Fortran, on many platforms, instruction-set architectures and operating syst ...
,
OpenHMPP OpenHMPP (HMPP for Hybrid Multicore Parallel Programming) - programming standard for heterogeneous computing. Based on a set of compiler directives, standard is a programming model designed to handle hardware accelerators without the complexity ...
, FastFlow, Skandium,
MPI MPI or Mpi may refer to: Science and technology Biology and medicine * Magnetic particle imaging, an emerging non-invasive tomographic technique * Myocardial perfusion imaging, a nuclear medicine procedure that illustrates the function of the hear ...
, and Erlang can be used on multi-core platforms. Intel introduced a new abstraction for C++ parallelism called TBB. Other research efforts include the Codeplay Sieve System, Cray's
Chapel A chapel is a Christian place of prayer and worship that is usually relatively small. The term has several meanings. Firstly, smaller spaces inside a church that have their own altar are often called chapels; the Lady chapel is a common type ...
, Sun's
Fortress A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...
, and IBM's X10. Multi-core processing has also affected the ability of modern computational software development. Developers programming in newer languages might find that their modern languages do not support multi-core functionality. This then requires the use of numerical libraries to access code written in languages like C and Fortran, which perform math computations faster than newer languages like C#. Intel's MKL and AMD's
ACML AMD Core Math Library (ACML) is an end-of-life software development library released by AMD. This library provides mathematical routines optimized for AMD processors. The successor to ACML is the AMD Optimizing CPU Libraries (AOCL), a set of mostl ...
are written in these native languages and take advantage of multi-core processing. Balancing the application workload across processors can be problematic, especially if they have different performance characteristics. There are different conceptual models to deal with the problem, for example using a coordination language and program building blocks (programming libraries or higher-order functions). Each block can have a different native implementation for each processor type. Users simply program using these abstractions and an intelligent compiler chooses the best implementation based on the context. Managing concurrency acquires a central role in developing parallel applications. The basic steps in designing parallel applications are: ; Partitioning : The partitioning stage of a design is intended to expose opportunities for parallel execution. Hence, the focus is on defining a large number of small tasks in order to yield what is termed a fine-grained decomposition of a problem. ; Communication : The tasks generated by a partition are intended to execute concurrently but cannot, in general, execute independently. The computation to be performed in one task will typically require data associated with another task. Data must then be transferred between tasks so as to allow computation to proceed. This information flow is specified in the communication phase of a design. ; Agglomeration : In the third stage, development moves from the abstract toward the concrete. Developers revisit decisions made in the partitioning and communication phases with a view to obtaining an algorithm that will execute efficiently on some class of parallel computer. In particular, developers consider whether it is useful to combine, or agglomerate, tasks identified by the partitioning phase, so as to provide a smaller number of tasks, each of greater size. They also determine whether it is worthwhile to replicate data and computation. ; Mapping : In the fourth and final stage of the design of parallel algorithms, the developers specify where each task is to execute. This mapping problem does not arise on uniprocessors or on shared-memory computers that provide automatic task scheduling. On the other hand, on the
server side In the client–server model, server-side refers to programs and operations that run on the server. This is in contrast to client-side programs and operations which run on the client. General concepts Typically, a server is a computer applicatio ...
, multi-core processors are ideal because they allow many users to connect to a site simultaneously and have independent threads of execution. This allows for Web servers and application servers that have much better
throughput Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel, such as Ethernet or packet radio, in a communication network. The data that these messages contain may be delivered ove ...
.


Licensing

Vendors may license some software "per processor". This can give rise to ambiguity, because a "processor" may consist either of a single core or of a combination of cores. * Initially, for some of its enterprise software,
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
continued to use a per-
socket Socket may refer to: Mechanics * Socket wrench, a type of wrench that uses separate, removable sockets to fit different sizes of nuts and bolts * Socket head screw, a screw (or bolt) with a cylindrical head containing a socket into which the hexag ...
licensing system. However, for some software such as BizTalk Server 2013, SQL Server 2014, and Windows Server 2016, Microsoft has shifted to per-core licensing. *
Oracle Corporation Oracle Corporation is an American multinational computer technology corporation headquartered in Austin, Texas. In 2020, Oracle was the third-largest software company in the world by revenue and market capitalization. The company sells da ...
counts an AMD X2 or an Intel dual-core CPU as a single processor but uses other metrics for other types, especially for processors with more than two cores.


Embedded applications

Embedded computing An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' a ...
operates in an area of processor technology distinct from that of "mainstream" PCs. The same technological drives towards multi-core apply here too. Indeed, in many cases the application is a "natural" fit for multi-core technologies, if the task can easily be partitioned between the different processors. In addition, embedded software is typically developed for a specific hardware release, making issues of
software portability A computer program is said to be portable if there is very low effort required to make it run on different platforms. The pre-requirement for portability is the generalized abstraction between the application logic and system interfaces. When ...
, legacy code or supporting independent developers less critical than is the case for PC or enterprise computing. As a result, it is easier for developers to adopt new technologies and as a result there is a greater variety of multi-core processing architectures and suppliers.


Network processors

, multi-core network processors have become mainstream, with companies such as
Freescale Semiconductor Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, em ...
,
Cavium Networks Cavium was a fabless semiconductor company based in San Jose, California, specializing in ARM-based and MIPS-based network, video and security processors and SoCs. The company was co-founded in 2000 by Syed B. Ali and M. Raghib Hussain, who ...
, Wintegra and
Broadcom Broadcom Inc. is an American designer, developer, manufacturer and global supplier of a wide range of semiconductor and infrastructure software products. Broadcom's product offerings serve the data center, networking, software, broadband, wirel ...
all manufacturing products with eight processors. For the system developer, a key challenge is how to exploit all the cores in these devices to achieve maximum networking performance at the system level, despite the performance limitations inherent in a
symmetric multiprocessing Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all ...
(SMP) operating system. Companies such as 6WIND provide portable packet processing software designed so that the networking data plane runs in a fast path environment outside the operating system of the network device.


Digital signal processing

In
digital signal processing Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are ...
the same trend applies:
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...
has the three-core TMS320C6488 and four-core TMS320C5441,
Freescale Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, embedd ...
the four-core MSC8144 and six-core MSC8156 (and both have stated they are working on eight-core successors). Newer entries include the Storm-1 family fro
Stream Processors, Inc
with 40 and 80 general purpose ALUs per chip, all programmable in C as a SIMD engine and
Picochip Picochip was a venture-backed fabless semiconductor company based in Bath, England, founded in 2000. In January 2012 Picochip was acquired by Mindspeed Technologies, Inc and subsequently by Intel. The company was active in two areas, with two dist ...
with 300 processors on a single die, focused on communication applications.


Heterogeneous systems

In
heterogeneous computing Heterogeneous computing refers to systems that use more than one kind of processor or cores. These systems gain performance or energy efficiency not just by adding the same type of processors, but by adding dissimilar coprocessors, usually incor ...
, where a system uses more than one kind of processor or cores, multi-core solutions are becoming more common:
Xilinx Xilinx, Inc. ( ) was an American technology and semiconductor company that primarily supplied programmable logic devices. The company was known for inventing the first commercially viable field-programmable gate array (FPGA) and creating the fi ...
Zynq UltraScale+ MPSoC has a quad-core ARM Cortex-A53 and dual-core ARM Cortex-R5. Software solutions such as OpenAMP are being used to help with inter-processor communication. Mobile devices may use the
ARM big.LITTLE ARM big.LITTLE is a heterogeneous computing architecture developed by ARM Holdings, coupling relatively battery-saving and slower processor cores (''LITTLE'') with relatively more powerful and power-hungry ones (''big''). Typically, only one "s ...
architecture.


Hardware examples


Commercial

*
Adapteva Zero ASIC Corporation, formerly Adapteva, Inc., is a fabless semiconductor company focusing on low power many core microprocessor design. The company was the second company to announce a design with 1,000 specialized processing cores on a single ...
Epiphany, a many-core processor architecture which allows up to 4096 processors on-chip, although only a 16-core version has been commercially produced. *
Aeroflex Gaisler Aeroflex Inc. was an American company which produced test equipment, RF and microwave integrated circuits, components and systems used for wireless communications. Its headquarters were located in Plainview, New York. In May 2014, Aeroflex was ...
LEON3, a multi-core
SPARC SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system develope ...
that also exists in a fault-tolerant version. *
Ageia Ageia, founded in 2002, was a fabless semiconductor company. In 2004, Ageia acquired NovodeX, the company who created PhysX – a Physics Processing Unit chip capable of performing game physics calculations much faster than general purpose CPUs ...
PhysX, a multi-core physics processing unit. *
Ambric Ambric, Inc. was a designer of computer processors that developed the Ambric architecture. Its Am2045 Massively Parallel Processor Array (MPPA) chips were primarily used in high-performance embedded systems such as medical imaging, video, and signa ...
Am2045, a 336-core Massively Parallel Processor Array (MPPA) * AMD ** A-Series, dual-, triple-, and quad-core of Accelerated Processor Units (APU). ** Athlon 64 FX and
Athlon 64 X2 The Athlon 64 X2 is the first native dual-core desktop central processing unit (CPU) designed by Advanced Micro Devices (AMD). It was designed from scratch as native dual-core by using an already multi-CPU enabled Athlon 64, joining it with anot ...
single- and dual-core desktop processors. ** Athlon II, dual-, triple-, and quad-core desktop processors. ** FX-Series, quad-, 6-, and 8-core desktop processors. **
Opteron Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''Sledg ...
, single-, dual-, quad-, 6-, 8-, 12-, and 16-core server/workstation processors. ** Phenom, dual-, triple-, and quad-core processors. **
Phenom II Phenom II is a family of AMD's multi-core 45 nm processors using the AMD K10 microarchitecture, succeeding the original Phenom. Advanced Micro Devices released the Socket AM2+ version of Phenom II in December 2008, while Socket AM3 version ...
, dual-, triple-, quad-, and 6-core desktop processors. ** Sempron, single-, dual-, and quad-core entry level processors. ** Turion, single- and dual-core laptop processors. **
Ryzen Ryzen ( ) is a brand of multi-core x86-64 microprocessors designed and marketed by AMD for desktop, mobile, server, and embedded platforms based on the Zen microarchitecture. It consists of central processing units (CPUs) marketed for mainst ...
, dual-, quad-, 6-, 8-, 12-, 16-, 24-, 32-, and 64-core desktop, mobile, and embedded platform processors. **
Epyc Epyc is a brand of multi-core x86-64 microprocessors designed and sold by AMD, based on the company's Zen microarchitecture. Introduced in June 2017, they are specifically targeted for the server and embedded system markets. Epyc processors share ...
, quad-, 8-, 12-, 16-, 24-, 32-, and 64-core server and embedded processors. **
Radeon Radeon () is a brand of computer products, including graphics processing units, random-access memory, RAM disk software, and solid-state drives, produced by Radeon Technologies Group, a division of AMD. The brand was launched in 2000 by ATI Tech ...
and FireStream
GPU A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobi ...
/
GPGPU General-purpose computing on graphics processing units (GPGPU, or less often GPGP) is the use of a graphics processing unit (GPU), which typically handles computation only for computer graphics, to perform computation in applications traditiona ...
. *
Analog Devices Analog Devices, Inc. (ADI), also known simply as Analog, is an American multinational semiconductor company specializing in data conversion, signal processing and power management technology, headquartered in Wilmington, Massachusetts. The ...
Blackfin The Blackfin is a family of 16-/32-bit microprocessors developed, manufactured and marketed by Analog Devices. The processors have built-in, fixed-point digital signal processor (DSP) functionality supplied by 16-bit multiply–accumulates ( ...
BF561, a symmetrical dual-core processor *
ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...
MPCore is a fully synthesizable multi-core container for
ARM11 MPCore ARM11 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings. The ARM11 core family consists of ARM1136J(F)-S, ARM1156T2(F)-S, ARM1176JZ(F)-S, and ARM11MPCore. Since ARM11 cores were released from 2002 to 2005, they are no lon ...
and
ARM Cortex-A9 MPCore The ARM Cortex-A9 MPCore is a 32-bit multi-core processor that provides up to 4 cache-coherent cores, each implementing the ARM v7 architecture instruction set. It was introduced in 2007. Features Key features of the Cortex-A9 core are: * ...
processor cores, intended for high-performance embedded and entertainment applications. * ASOCS ModemX, up to 128 cores, wireless applications. *
Azul Systems Azul Systems, Inc. develops runtimes ( JDKs, JVMs) for executing Java-based applications. Founded in March 2002, Azul Systems is headquartered in Sunnyvale, California Products Azul Platform Prime (Formerly Zing) Azul produces ''Platform ...
** Vega 1, a 24-core processor, released in 2005. ** Vega 2, a 48-core processor, released in 2006. ** Vega 3, a 54-core processor, released in 2008. * Broadcom SiByte SB1250, SB1255, SB1455; BCM 2836 quad-core ARM SoC (designed for the
Raspberry Pi Raspberry Pi () is a series of small single-board computers (SBCs) developed in the United Kingdom by the Raspberry Pi Foundation in association with Broadcom. The Raspberry Pi project originally leaned towards the promotion of teaching basic ...
2) *
Cadence Design Systems Cadence Design Systems, Inc. (stylized as cādence), headquartered in San Jose, California, is an American multinational computational software company, founded in 1988 by the merger of SDA Systems and ECAD, Inc. The company produces software, ...
Tensilica Xtensa LX6, available in a dual-core configuration in Espressif Systems's
ESP32 ESP32 is a series of low-cost, low-power system on a chip microcontrollers with integrated Wi-Fi and dual-mode Bluetooth. The ESP32 series employs either a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations, Xtensa ...
*
ClearSpeed ClearSpeed Technology Ltd was a semiconductor company, formed in 2002 to develop enhanced SIMD processors for use in high-performance computing and embedded systems. Based in Bristol, UK, the company has been selling its processors since 2005. ...
** CSX700, 192-core processor, released in 2008 (32/64-bit floating point; Integer ALU). * Cradle Technologies CT3400 and CT3600, both multi-core DSPs. *
Cavium Networks Cavium was a fabless semiconductor company based in San Jose, California, specializing in ARM-based and MIPS-based network, video and security processors and SoCs. The company was co-founded in 2000 by Syed B. Ali and M. Raghib Hussain, who ...
Octeon, a 32-core MIPS MPU.
Coherent Logixhx3100 Processor
a 100-core DSP/GPP processor. *
Freescale Semiconductor Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, em ...
QorIQ series processors, up to 8 cores,
Power ISA Power ISA is a reduced instruction set computer (RISC) instruction set architecture (ISA) currently developed by the OpenPOWER Foundation, led by IBM. It was originally developed by IBM and the now-defunct Power.org industry group. Power ISA ...
MPU. *
Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...
PA-8800 The PA-8000 (PCX-U), code-named ''Onyx'', is a microprocessor developed and fabricated by Hewlett-Packard (HP) that implemented the PA-RISC 2.0 instruction set architecture (ISA). Hunt 1995 It was a completely new design with no circuitry derived ...
and
PA-8900 The PA-8000 (PCX-U), code-named ''Onyx'', is a microprocessor developed and fabricated by Hewlett-Packard (HP) that implemented the PA-RISC 2.0 instruction set architecture (ISA). Hunt 1995 It was a completely new design with no circuitry derived ...
, dual core
PA-RISC PA-RISC is an instruction set architecture (ISA) developed by Hewlett-Packard. As the name implies, it is a reduced instruction set computer (RISC) architecture, where the PA stands for Precision Architecture. The design is also referred to as ...
processors. * IBM **
POWER4 The POWER4 is a microprocessor developed by International Business Machines (IBM) that implemented the 64-bit PowerPC and PowerPC AS instruction set architectures. Released in 2001, the POWER4 succeeded the POWER3 and RS64 microprocessors, ena ...
, a dual-core
PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple– IBM– ...
processor, released in 2001. ** POWER5, a dual-core PowerPC processor, released in 2004. **
POWER6 The POWER6 is a microprocessor developed by IBM that implemented the Power ISA v.2.03. When it became available in systems in 2007, it succeeded the POWER5+ as IBM's flagship Power microprocessor. It is claimed to be part of the eCLipz projec ...
, a dual-core PowerPC processor, released in 2007. **
POWER7 POWER7 is a family of superscalar multi-core microprocessors based on the Power ISA 2.06 instruction set architecture released in 2010 that succeeded the POWER6 and POWER6+. POWER7 was developed by IBM at several sites including IBM's Roche ...
, a 4,6,8-core PowerPC processor, released in 2010. **
POWER8 POWER8 is a family of superscalar multi-core microprocessors based on the Power ISA, announced in August 2013 at the Hot Chips conference. The designs are available for licensing under the OpenPOWER Foundation, which is the first time for ...
, a 12-core PowerPC processor, released in 2013. **
POWER9 POWER9 is a family of superscalar, multithreading, multi-core microprocessors produced by IBM, based on the Power ISA. It was announced in August 2016. The POWER9-based processors are being manufactured using a 14 nm FinFET process, in ...
, a 12 or 24-core PowerPC processor, released in 2017. **
Power10 Power10 is a superscalar, multithreading, multi-core microprocessor family, based on the open source Power ISA, and announced in August 2020 at the Hot Chips conference; systems with Power10 CPUs. Generally available from September 2021 in ...
, a 15 or 30-core PowerPC processor, released in 2021. **
PowerPC 970 The PowerPC 970, PowerPC 970FX, and PowerPC 970MP are 64-bit PowerPC processors from IBM introduced in 2002. When used in PowerPC-based Macintosh computers, Apple referred to them as the PowerPC G5. The 970 family was created through a collab ...
MP, a dual-core PowerPC processor, used in the Apple
Power Mac G5 The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and ...
. **
Xenon Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...
, a triple-core, SMT-capable, PowerPC microprocessor used in the
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generati ...
game console. ** z10, a quad-core
z/Architecture z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architect ...
processor, released in 2008. ** z196, a quad-core z/Architecture processor, released in 2010. ** zEC12, a six-core z/Architecture processor, released in 2012. ** z13, an eight-core z/Architecture processor, released in 2015. ** z14, a ten-core z/Architecture processor, released in 2017. ** z15, a twelve-core z/Architecture processor, released in 2019. ** Telum, an eight-core z/Architecture processor, released in 2021. *
Infineon Infineon Technologies AG is a German semiconductor manufacturer founded in 1999, when the semiconductor operations of the former parent company Siemens AG were spun off. Infineon has about 50,280 employees and is one of the ten largest semicond ...
** AURIX ** Danube, a dual-core, MIPS-based, home gateway processor. *
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...
**
Atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, a ...
, single, dual-core, quad-core, 8-, 12-, and 16-core processors for
netbooks Netbook was a commonly used term that identified a product class of small and inexpensive laptops which were sold from 2007 to around 2013. These machines were designed primarily as cost-effective tools for consumers to access the Inte ...
,
nettops A nettop (or miniature PC, Mini PC or Smart Micro PC) is a small-sized, inexpensive, low-power, Legacy free PC, legacy-free desktop computer, desktop computer designed for basic tasks such as Web navigation, web browsing, accessing web applicat ...
, embedded applications, and mobile internet devices (MIDs). ** Atom SoC (system on a chip), single-core, dual-core, and quad-core processors for smartphones and tablets. **
Celeron Celeron is Intel's brand name for low-end IA-32 and x86-64 computer microprocessor models targeted at low-cost personal computers. Celeron processors are compatible with IA-32 software. They typically offer less performance per clock speed co ...
, the first dual-core (and, later, quad-core) processor for the budget/entry-level market. **
Core Duo Intel Core is a line of streamlined midrange consumer, workstation and enthusiast computer central processing units (CPUs) marketed by Intel Corporation. These processors displaced the existing mid- to high-end Pentium processors at the time o ...
, a dual-core processor. ** Core 2 Duo, a dual-core processor. ** Core 2 Quad, 2 dual-core dies packaged in a multi-chip module. **
Core i3 Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...
, Core i5,
Core i7 The following is a list of Intel Core i7 brand microprocessors. Introduced in 2008, the Core i7 line of microprocessors are intended to be used by high-end users. Desktop processors Nehalem microarchitecture (1st generation) "Bloomfield" ...
and
Core i9 The following is a list of Intel Core i9 brand microprocessors. They were introduced in May 2017 for LGA 2066 chips, also known as Intel Core X-series processors. With their high number of cores, high power draw, high thermal output, and high pe ...
, a family of dual-, quad-, 6-, 8-, 10-, 12-, 14-, 16-, and 18-core processors, and the successor of the Core 2 Duo and the Core 2 Quad. **
Itanium Itanium ( ) is a discontinued family of 64-bit Intel microprocessors that implement the Intel Itanium architecture (formerly called IA-64). Launched in June 2001, Intel marketed the processors for enterprise servers and high-performance comput ...
, single, dual-core, quad-core, and 8-core processors. **
Pentium Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and P ...
, single, dual-core, and quad-core processors for the entry-level market. **
Teraflops Research Chip Intel Teraflops Research Chip (codenamed ''Polaris'') is a research manycore processor containing 80 cores, using a network-on-chip architecture, developed by Intel's Tera-Scale Computing Research Program. It was manufactured using a 65 n ...
(Polaris), a 3.16 GHz, 80-core processor prototype, which the company originally stated would be released by 2011. **
Xeon Xeon ( ) is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded system markets. It was introduced in June 1998. Xeon processors are based on the same ar ...
dual-, quad-, 6-, 8-, 10-, 12-, 14-, 15-, 16-, 18-, 20-, 22-, 24-, 26-, 28-, 32-, 48-, and 56-core processors. **
Xeon Phi Xeon Phi was a series of x86 manycore processors designed and made by Intel. It was intended for use in supercomputers, servers, and high-end workstations. Its architecture allowed use of standard programming languages and application program ...
57-, 60-, 61-, 64-, 68-, and 72-core processors. * IntellaSys ** SEAforth 40C18, a 40-core processor. ** SEAforth24, a 24-core processor designed by
Charles H. Moore Charles Havice Moore II (born 9 September 1938), better known as Chuck Moore, is an American computer engineer and programmer, best known for inventing the Forth programming language in 1968. He cofounded FORTH, Inc., with Elizabeth Rather in ...
. * Kalray ** MPPA-256, 256-core processor, released 2012 (256 usable VLIW cores, Network-on-Chip (NoC), 32/64-bit IEEE 754 compliant FPU) * NetLogic Microsystems ** XLP, a 32-core, quad-threaded
MIPS64 MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, ...
processor. ** XLR, an eight-core, quad-threaded MIPS64 processor. ** XLS, an eight-core, quad-threaded MIPS64 processor. *
Nvidia Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...
** RTX 3090 (10496 CUDA cores,
GPGPU General-purpose computing on graphics processing units (GPGPU, or less often GPGP) is the use of a graphics processing unit (GPU), which typically handles computation only for computer graphics, to perform computation in applications traditiona ...
cores; plus other more specialized cores). *
Parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby object ...
Propeller P8X32, an eight-core microcontroller. *
picoChip Picochip was a venture-backed fabless semiconductor company based in Bath, England, founded in 2000. In January 2012 Picochip was acquired by Mindspeed Technologies, Inc and subsequently by Intel. The company was active in two areas, with two dist ...
PC200 series 200–300 cores per device for DSP & wireless. * Plurality HAL series tightly coupled 16-256 cores, L1 shared memory, hardware synchronized processor. * Rapport Kilocore KC256, a 257-core microcontroller with a PowerPC core and 256 8-bit "processing elements". * SiCortex "SiCortex node" has six MIPS64 cores on a single chip. * SiFive ** U74 includes 4 cores *
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
/ IBM/
Toshiba , commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, ...
's
Cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...
processor, a nine-core processor with one general purpose
PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple– IBM– ...
core and eight specialized SPUs (Synergistic Processing Unit) optimized for vector operations used in the
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed by Sony Interactive Entertainment, Sony Computer Entertainment. The successor to the PlayStation 2, it is part of the PlayStation brand of consoles. It was first released on Novemb ...
. *
Sun Microsystems Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, t ...
**
MAJC MAJC (Microprocessor Architecture for Java Computing) was a Sun Microsystems multi-core, multithreaded, very long instruction word (VLIW) microprocessor design from the mid-to-late 1990s. Originally called the UltraJava processor, the MAJC process ...
5200, two-core VLIW processor. **
UltraSPARC IV The UltraSPARC IV ''Jaguar'' and follow-up UltraSPARC IV+ ''Panther'' are microprocessors designed by Sun Microsystems and manufactured by Texas Instruments. They are the fourth generation of UltraSPARC microprocessors, and implement the 64-bit S ...
and UltraSPARC IV+, dual-core processors. ** UltraSPARC T1, an eight-core, 32-thread processor. ** UltraSPARC T2, an eight-core, 64-concurrent-thread processor. **
UltraSPARC T3 The UltraSPARC is a microprocessor developed by Sun Microsystems and fabricated by Texas Instruments, introduced in mid-1995. It is the first microprocessor from Sun to implement the 64-bit SPARC V9 instruction set architecture (ISA). Marc Tremb ...
, a sixteen-core, 128-concurrent-thread processor. ** SPARC T4, an eight-core, 64-concurrent-thread processor. **
SPARC T5 SPARC T5 is the fifth generation multicore microprocessor of Oracle's SPARC T series family. It was first presented at Hot Chips 24 in August 2012, and was officially introduced with the Oracle SPARC T5 servers in March 2013. The processor is ...
, a sixteen-core, 128-concurrent-thread processor. * Sunway **
Sunway SW26010 The SW26010 is a 260-core manycore processor designed by the Shanghai Integrated Circuit Technology and Industry Promotion Center (ICC for short)( Chinese: 上海集成电路技术与产业促进中心 (简称ICC)). It implements the Sunway architec ...
, a 260-core processor used in the
Sunway TaihuLight The Sunway TaihuLight ( ''Shénwēi·tàihú zhī guāng'') is a Chinese supercomputer which, , is ranked fourth in the TOP500 list, with a LINPACK benchmark rating of 93 petaflops. The name is translated as ''divine power, the light of Taihu Lak ...
. *
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...
** TMS320C80 MVP, a five-core multimedia video processor. ** TMS320TMS320C66, 2,4,8 core DSP. * Tilera **
TILE64 TILE64 is a VLIW ISA multicore processor manufactured by Tilera. It consists of a mesh network of 64 "tiles", where each tile houses a general purpose processor, cache, and a non-blocking router, which the tile uses to communicate with the o ...
, a 64-core 32-bit processor. **
TILE-Gx TILE-Gx is a VLIW ISA multicore processor family by Tilera. It consists of a mesh network of up to 100 cores. It is to be produced by TSMC Taiwan Semiconductor Manufacturing Company Limited (TSMC; also called Taiwan Semiconductor) is a Tai ...
, a 72-core 64-bit processor. *
XMOS XMOS is a fabless semiconductor company that develops audio products and multicore microcontrollers. Company history XMOS was founded in July 2005 by Ali Dixon, James Foster, Noel Hurley, David May, and Hitesh Mehta. It received seed funding ...
Software Defined Silicon XMOS is a fabless semiconductor company that develops audio products and multicore microcontrollers. Company history XMOS was founded in July 2005 by Ali Dixon, James Foster, Noel Hurley, David May, and Hitesh Mehta. It received seed funding ...
quad-core XS1-G4.


Free

*
OpenSPARC OpenSPARC is an open-source hardware project started in December 2005. The initial contribution to the project was Sun Microsystems' register-transfer level (RTL) Verilog code for a full 64-bit, 32- thread microprocessor, the UltraSPARC T1 processor ...


Academic

*
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
, 16-cor
RAW
processor *
University of California, Davis The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The inst ...
,
Asynchronous array of simple processors Asynchrony is the state of not being in synchronization. Asynchrony or asynchronous may refer to: Electronics and computing * Asynchrony (computer programming), the occurrence of events independent of the main program flow, and ways to deal with ...
(AsAP) ** 36-core 610 MHz AsAP ** 167-core 1.2 GHz AsAP2 *
University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seatt ...

Wavescalar
processor *
University of Texas, Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...
,
TRIPS The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) is an international legal agreement between all the member nations of the World Trade Organization (WTO). It establishes minimum standards for the regulation by nat ...
processor *
Linköping University Linköping University (, LiU) is a public research university based in Linköping, Sweden. Originally established in 1969, it was granted full university status in 1975 and is one of Sweden's largest academic institutions. The university has fou ...
, Sweden, ePUMA processor *
UC Davis The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The institu ...
, Kilocore, a 1000 core 1.78 GHz processor on a 32 nm IBM process


Benchmarks

The research and development of multicore processors often compares many options, and benchmarks are developed to help such evaluations. Existing benchmarks include SPLASH-2, PARSEC, and COSMIC for heterogeneous systems.


See also

*
CPU shielding CPU shielding is a practice where on a multiprocessor system or on a CPU with multiple cores, real-time tasks can run on one CPU or core while non-real-time tasks run on another. The operating system must be able to set a CPU affinity for both p ...
*
CUDA CUDA (or Compute Unified Device Architecture) is a parallel computing platform and application programming interface (API) that allows software to use certain types of graphics processing units (GPUs) for general purpose processing, an approach ...
*
GPGPU General-purpose computing on graphics processing units (GPGPU, or less often GPGP) is the use of a graphics processing unit (GPU), which typically handles computation only for computer graphics, to perform computation in applications traditiona ...
*
Hyper-threading Hyper-threading (officially called Hyper-Threading Technology or HT Technology and abbreviated as HTT or HT) is Intel's proprietary simultaneous multithreading (SMT) implementation used to improve parallelization of computations (doing multipl ...
*
Manycore Manycore processors are special kinds of multi-core processors designed for a high degree of parallel processing, containing numerous simpler, independent processor cores (from a few tens of cores to thousands or more). Manycore processors are u ...
*
Multicore Association The Multicore Association was founded in 2005. Multicore Association is a member-funded, non-profit, industry consortium focused on the creation of open standard APIs, specifications, and guidelines that allow system developers and programmers ...
* Multitasking *
OpenCL OpenCL (Open Computing Language) is a software framework, framework for writing programs that execute across heterogeneous computing, heterogeneous platforms consisting of central processing units (CPUs), graphics processing units (GPUs), d ...
(Open Computing Language) – a framework for heterogeneous execution * Parallel random access machine *
Partitioned global address space In computer science, partitioned global address space (PGAS) is a parallel programming model paradigm. PGAS is typified by communication operations involving a global memory address space abstraction that is logically partitioned, where a portio ...
(PGAS) *
Race condition A race condition or race hazard is the condition of an electronics, software, or other system where the system's substantive behavior is Sequential logic, dependent on the sequence or timing of other uncontrollable events. It becomes a software ...
* Thread


Notes

#
Digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio s ...
s (DSPs) have used multi-core architectures for much longer than high-end general-purpose processors. A typical example of a DSP-specific implementation would be a combination of a
RISC In computer engineering, a reduced instruction set computer (RISC) is a computer designed to simplify the individual instructions given to the computer to accomplish tasks. Compared to the instructions given to a complex instruction set comp ...
CPU and a DSP MPU. This allows for the design of products that require a general-purpose processor for user interfaces and a DSP for real-time data processing; this type of design is common in
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
s. In other applications, a growing number of companies have developed multi-core DSPs with very large numbers of processors. # Two types of
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s are able to use a dual-CPU multiprocessor: partitioned multiprocessing and
symmetric multiprocessing Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all ...
(SMP). In a partitioned architecture, each CPU boots into separate segments of physical memory and operate independently; in an SMP OS, processors work in a shared space, executing threads within the OS independently.


References


Further reading

* *


External links


"What Is a Processor Core?"
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"Embedded moves to multicore"
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"Multicore Is Bad News for Supercomputers"
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IEEE Spectrum ''IEEE Spectrum'' is a magazine edited by the Institute of Electrical and Electronics Engineers. The first issue of ''IEEE Spectrum'' was published in January 1964 as a successor to ''Electrical Engineering''. The magazine contains peer-reviewe ...
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Architecting solutions for the Manycore future
published on Feb 19, 2010 (more than one dead link in the slide) {{Authority control Computer architecture Digital signal processing Flynn's taxonomy Microprocessors Parallel computing