Ingo Molnár, employed by

Red Hat Red Hat, Inc. (formerly Red Hat Software, Inc.) is an American software company that provides open source software products to enterprises and is a subsidiary of IBM. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North ...

as of May 2013, is a Hungarian

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

hacker A hacker is a person skilled in information technology who achieves goals and solves problems by non-standard means. The term has become associated in popular culture with a security hackersomeone with knowledge of bug (computing), bugs or exp ...

. He is known for his contributions to the operating system in terms of

security Security is protection from, or resilience against, potential harm (or other unwanted coercion). Beneficiaries (technically referents) of security may be persons and social groups, objects and institutions, ecosystems, or any other entity or ...

and

performance A performance is an act or process of staging or presenting a play, concert, or other form of entertainment. It is also defined as the action or process of carrying out or accomplishing an action, task, or function. Performance has evolved glo ...

Life and career

Molnár studied at

Eötvös Loránd University Eötvös Loránd University (, ELTE, also known as ''University of Budapest'') is a Hungarian public research university based in Budapest. Founded in 1635, ELTE is one of the largest and most prestigious public higher education institutions in ...

Work

Some of his additions to the Linux

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...

include the O(1) scheduler of Linux-2.6.0 and the

Completely Fair Scheduler The Completely Fair Scheduler (CFS) was a process scheduler that was merged into the 2.6.23 (October 2007) release of the Linux Linux kernel, kernel. It was the default scheduler of the tasks of the SCHED_NORMAL class (i.e., tasks that have no re ...

of Linux-2.6.23, the in-kernel TUX

HTTP HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, wher ...

FTP The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and dat ...

server Server may refer to: Computing *Server (computing), a computer program or a device that provides requested information for other programs or devices, called clients. Role * Waiting staff, those who work at a restaurant or a bar attending custome ...

, as well as his work to enhance thread handling. He also wrote a kernel security feature called "

Exec Shield Exec Shield is a project started at Red Hat, Inc in late 2002 with the aim of reducing the risk of worm or other automated remote attacks on Linux systems. The first result of the project was a security patch for the Linux kernel that emulates an ...

", which prevents stack-based buffer overflow exploits in the

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel, based on the 8086 microprocessor and its 8-bit-external-bus variant, the 8088. Th ...

architecture by disabling the

execute Execution, in capital punishment Capital punishment, also known as the death penalty and formerly called judicial homicide, is the state-sanctioned killing of a person as punishment for actual or supposed misconduct. The sentence (law), s ...

permission for the stack. Together with Thomas Gleixner, he worked on the real-time preemption (

PREEMPT_RT PREEMPT_RT was a set of out-of-tree patches for the Linux kernel which implement both hard and soft real-time computing capabilities. On September 20, 2024, PREEMPT_RT was fully merged and enabled in mainline Linux on the supported architectur ...

) patch set, which aims to reduce the maximum

thread switching latency In computing, a context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point, and then restoring a different, previously saved, state. This allows multiple processes ...

of the Linux kernel from an unbounded number of milliseconds to down to bounded values in the order of tens of microseconds (depending on the system). As of 2011, Thomas Gleixner is working on further improving the patch and getting important infrastructure patches of the patch set merged into the Mainline Linux kernel. Between Linux 2.6.21 and Linux 2.6.24, he worked on the

(CFS) which was inspired by the scheduler work of

Con Kolivas Con Kolivas is a Greek-Australian anaesthetist.Anaesthesia Information Page
by Kolivas, Jan 2001

. CFS replaced the previous

process scheduler In computing, scheduling is the action of assigning resources to perform tasks. The resources may be processors, network links or expansion cards. The tasks may be threads, processes or data flows. The scheduling activity is carried out by ...

of the Linux kernel with Linux-2.6.23. In 2012 Molnar criticized the

Linux desktop Besides the Linux distributions designed for general-purpose use on desktops and servers, distributions may be specialized for different purposes including computer architecture support, embedded systems, stability, security, localization to a spe ...

as "not free enough" for the users with respect to the applications. He argues that the typically used system of software distribution and deployment by a centrally organized

Linux distribution A Linux distribution, often abbreviated as distro, is an operating system that includes the Linux kernel for its kernel functionality. Although the name does not imply product distribution per se, a distro—if distributed on its own—is oft ...

s is not fast and flexible enough to satisfy the requirements of users and application producers alike. Molnár suggests a decentral deployment method (similar to Autopackage, Zero Install, or the Klik-successor

AppImage AppImage (formerly known as klik and PortableLinuxApps) is an open-source format for distributing portable software on Linux. It aims to allow the installation of binary software independently of specific Linux distributions. As a result, one App ...

) which allows a more flexible application infrastructure formed by a stable platform and independent software providers. In early 2022, he submitted an RFC on a set of about 2300 patches, called "Fast Kernel Headers", that are intended to improve kernel compile times by 50-80% and at the same time significantly reduce the problems created by the hierarchy and dependencies of include files, the so-called "dependency hell".Ingo Molnar's patch cover letter
(2022-01-02)

Quotes

On the question, why the

has not been adopted by the mainstream users yet:

References

External links

Ingo Molnár's homepage at Red Hat

Ingo Molnár's RT-kernel homepage

The RT-kernel Wiki

{{DEFAULTSORT:Molnar, Ingo Linux kernel programmers Living people Hungarian computer scientists Year of birth missing (living people) Free software programmers Hungarian computer programmers Red Hat employees