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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 processor architectures. Details The term ''multithreading'' is ambiguous, because not only can multiple threads be executed simultaneously on one CPU core, but also multiple tasks (with different page tables, different task state segments, different protection rings, different I/O permissions, etc.). Although running on the same core, they are completely separated from each other. Multithreading is similar in concept to preemptive multitasking but is implemented at the thread level of execution in modern superscalar processors. Simultaneous multithreading (SMT) is one of the two main implementations of multithreading, the other form being temporal multithreading (also known as super-threading). In temporal multithreading, only one thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superscalar
A superscalar processor (or multiple-issue 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 superscalar processor can execute or start executing more than one instruction during a clock cycle by simultaneously dispatching multiple instructions to different execution units on the processor. It therefore allows more throughput (the number of instructions that can be executed in a unit of time which can even be less than 1) than would otherwise be possible at a given clock rate. Each execution unit is not a separate processor (or a core if the processor is a multi-core processor), but an execution resource within a single CPU such as an arithmetic logic unit. While a superscalar CPU is typically also pipelined, superscalar and pipelining execution are considered different performance enhancement techni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrel Processor
A barrel processor is a CPU that switches between threads of execution on every cycle. This CPU design technique is also known as "interleaved" or "fine-grained" temporal multithreading. Unlike simultaneous multithreading in modern superscalar architectures, it generally does not allow execution of multiple instructions in one cycle. Like preemptive multitasking, each thread of execution is assigned its own program counter and other hardware registers (each thread's architectural state). A barrel processor can guarantee that each thread will execute one instruction every ''n'' cycles, unlike a preemptive multitasking machine, that typically runs one thread of execution for tens of millions of cycles, while all other threads wait their turn. A technique called C-slowing can automatically generate a corresponding barrel processor design from a single-tasking processor design. An ''n''-way barrel processor generated this way acts much like ''n'' separate multiprocessing copie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation Lookaside Buffer
A translation lookaside buffer (TLB) is a memory CPU cache, cache that stores the recent translations of virtual memory address to a physical memory Memory_address, location. It is used to reduce the time taken to access a user memory location. It can be called an address-translation cache. It is a part of the chip's Memory management unit, memory-management unit (MMU). A TLB may reside between the Central processing unit, CPU and the CPU cache, between CPU cache and the main memory or between the different levels of the multi-level cache. The majority of desktop, laptop, and server processors include one or more TLBs in the memory-management hardware, and it is nearly always present in any processor that uses Memory paging, paged or Memory segmentation, segmented virtual memory. The TLB is sometimes implemented as content-addressable memory (CAM). The CAM search key is the virtual address, and the search result is a physical address. If the requested address is present in the TLB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replay System
The replay system is a subsystem within the Intel Pentium 4 processor. Its primary function is to catch operations that have been mistakenly sent for execution by the processor's scheduler. Operations caught by the replay system are then re-executed in a loop until the conditions necessary for their proper execution have been fulfilled. Overview The replay system came about as a result of Intel's quest for ever-increasing clock speeds. These higher clock speeds necessitated very lengthy pipelines (up to 31 stages in the Prescott core). Because of this, there are six stages between the scheduler and the execution units in the Prescott core. In an attempt to maintain acceptable performance, Intel engineers had to design the scheduler to be very optimistic. The scheduler in a Pentium 4 processor is so aggressive that it will send operations for execution without a guarantee that they can be successfully executed. (Among other things, the scheduler assumes all data is in l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium 4
Pentium 4 is a series of single-core central processing unit, CPUs for Desktop computer, desktops, laptops and entry-level Server (computing), servers manufactured by Intel. The processors were shipped from November 20, 2000 until August 8, 2008. All Pentium 4 CPUs are based on the NetBurst microarchitecture, the successor to the P6 (microarchitecture), P6. The Pentium 4 #Willamette, Willamette (180 nm) introduced SSE2, while the #Prescott, Prescott (90 nm) introduced SSE3 and later 64-bit technology. Later versions introduced Hyper-threading, Hyper-Threading Technology (HTT). The first Pentium 4-branded processor to implement x86-64, 64-bit was the Prescott (90 nm) (February 2004), but this feature was not enabled. Intel subsequently began selling 64-bit Pentium 4s using the ''"E0" revision'' of the Prescotts, being sold on the OEM market as the Pentium 4, model F. The E0 revision also adds eXecute Disable (XD) (Intel's name for the NX bit) to Intel 64. Int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer components such as central processing units (CPUs) and related products for business and consumer markets. It is one of the world's List of largest semiconductor chip manufacturers, largest semiconductor chip manufacturers by revenue, and ranked in the Fortune 500, ''Fortune'' 500 list of the List of largest companies in the United States by revenue, largest United States corporations by revenue for nearly a decade, from 2007 to 2016 Fiscal year, fiscal years, until it was removed from the ranking in 2018. In 2020, it was reinstated and ranked 45th, being the List of Fortune 500 computer software and information companies, 7th-largest technology company in the ranking. It was one of the first companies listed on Nasdaq. Intel supplies List of I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compaq
Compaq Computer Corporation was an American information technology, information technology company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced some of the first IBM PC compatible computers, being the second company after Columbia Data Products to legally Reverse engineering, reverse engineer the BIOS of the IBM Personal Computer. It rose to become the Market share of personal computer vendors, largest supplier of PC systems during the 1990s. The company was initially based in Harris County, Texas. The company was formed by Rod Canion, Jim Harris (entrepreneur), Jim Harris, and Bill Murto, all of whom were former Texas Instruments senior managers. All three had left by 1991 under a shakeup, which saw Eckhard Pfeiffer appointed president and CEO, serving through the 1990s. Benjamin M. Rosen, Ben Rosen provided the venture capital financing for the fledgling company and served as chairman of the board for 17 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California, where the company would remain headquartered for the remainder of its lifetime; this HP Garage is now a designated landmark and marked with a plaque calling it the "Birthplace of 'Silicon Valley. HP developed and provided a wide variety of hardware components, as well as software and related services, to consumers, small and medium-sized businesses (small and medium-sized enterprises, SMBs), and fairly large companies, including customers in government sectors, until the company officially split into Hewlett Packard Enterprise and HP Inc. in 2015. HP initially produced a line of electronic test and measurement equipment. It won its first big contract in 1938 to provide the HP 200B, a variation of its first product, the HP 200A low-distor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until he was forced to resign in 1992, after the company had gone into precipitous decline. The company produced many different product lines over its history. It is best known for the work in the minicomputer market starting in the early 1960s. The company produced a series of machines known as the Programmed Data Processor, PDP line, with the PDP-8 and PDP-11 being among the most successful minis in history. Their success was only surpassed by another DEC product, the late-1970s VAX "supermini" systems that were designed to replace the PDP-11. Although a number of competitors had successfully competed with Digital through the 1970s, the VAX cemented the company's place as a leading vendor in the computer space. As microcomputers improved in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha 21464
The Alpha 21464 is an unfinished microprocessor that implements the Alpha instruction set architecture (ISA) developed by Digital Equipment Corporation and later by Compaq after it acquired Digital. The microprocessor was also known as EV8 (codenamed Araña). Slated for a 2004 release, it was canceled on 25 June 2001 when Compaq announced that Alpha would be phased out in favor of Itanium by 2004. When it was canceled, the Alpha 21464 was at a late stage of development but had not been taped out. The 21464's origins began in the mid-1990s when computer scientist Joel Emer was inspired by Dean Tullsen's research into simultaneous multithreading (SMT) at the University of Washington. Emer had researched the technology in the late 1990s and began to promote it once he was convinced of its value. Compaq made the announcement that the next Alpha microprocessor would use SMT in October 1999 at Microprocessor Forum 1999. At that time, it was expected that systems using the Alpha 21464 wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACS-1
The ACS-1 and ACS-360 are two related supercomputers designed by IBM as part of the Advanced Computing Systems project from 1965 to 1969. Although the designs were never finished and no models ever went into production, the project spawned a number of organizational techniques and architectural innovations that have since become incorporated into nearly all high-performance computers in existence today. Many of the ideas resulting from the project directly influenced the development of the IBM RS/6000 and, more recently, have contributed to the Explicitly Parallel Instruction Computing (EPIC) computing paradigm used by Intel and HP in the Itanium processors. After the ACS project folded, the engineers were given the choice to rejoin other divisions of IBM. Many declined as it would require them to return to the east coast from California. A number formed MASCOR in 1970 but this was short-lived as they were unable to raise capital. Gene Amdahl took the opportunity to start his ow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
