A Machine-Independent port of the MPD language run time system to NetBSD

SR (synchronizing resources) is a PASCAL - style language enhanced with constructs for concurrent programming developed at the University of Arizona in the late 1980s. MPD (presented in Gregory Andrews' book about Foundations of Multithreaded, Parallel, and Distributed Programming) is its successor, providing the same language primitives with a different, more C-style, syntax. The run-time system (in theory, identical, but not designed for sharing) of those languages provides the illusion of a multiprocessor machine on a single Unix-like system or a (local area) network of Unix-like machines. Chair V of the Computer Science Department of the University of Bonn is operating a laboratory for a practical course in parallel programming consisting of computing nodes running NetBSD/arm, normally used via PVM, MPI etc. We are considering to offer SR and MPD for this, too. As the original language distributions were only targeted at a few commercial Unix systems, some porting effort is needed. However, some of the porting effort of our earlier SR port should be reusable. The integrated POSIX threads support of NetBSD-2.0 and later allows us to use library primitives provided for NetBSD's phtread system to implement the primitives needed by the SR run-time system, thus implementing 13 target CPUs at once and automatically making use of SMP on VAX, Alpha, PowerPC, Sparc, 32-bit Intel and 64 bit AMD CPUs. We'll present some methods used for the impementation and compare some performance values to the traditional implementation.Comment: 6 page

A Linux kernel scheduler extension for multi-core systems

©2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The Linux kernel is mostly designed for multi-programed environments, but high-performance applications have other requirements. Such applications are run standalone, and usually rely on runtime systems to distribute the application's workload on worker threads, one per core. However, due to current OSes limitations, it is not feasible to track whether workers are actually running or blocked due to, for instance, a requested resource. For I/O intensive applications, this leads to a significant performance degradation given that the core of a blocked thread becomes idle until it is able to run again. In this paper, we present the proof-of-concept of a Linux kernel extension denoted User-Monitored Threads (UMT) which tackles this problem. Our extension allows a user-space process to be notified of when the selected threads become blocked or unblocked, making it possible for a runtime to schedule additional work on the idle core. We implemented the extension on the Linux Kernel 5.1 and adapted the Nanos6 runtime of the OmpSs-2 programming model to take advantage of it. The whole prototype was tested on two applications which, on the tested hardware and the appropriate conditions, reported speedups of almost 2x.This project is supported by the European Union’s Horizon 2021 research and innovation programme under the grant agreement No 754304 (DEEP-EST), the Ministry of Economy of Spain through the Severo Ochoa Center of Excellence Program (SEV-2015-0493), by the Spanish Ministry of Science and Innovation (contract TIN2015-65316-P) and by the Generalitat de Catalunya (2017-SGR-1481).Peer ReviewedPostprint (author's final draft

A Linux Kernel Scheduler Extension for Multi-core Systems

The Linux kernel is mostly designed for multi-programed environments, but high-performance applications have other requirements. Such applications are run standalone, and usually rely on runtime systems to distribute the application's workload on worker threads, one per core. However, due to current OSes limitations, it is not feasible to track whether workers are actually running or blocked due to, for instance, a requested resource. For I/O intensive applications, this leads to a significant performance degradation given that the core of a blocked thread becomes idle until it is able to run again. In this paper, we present the proof-of-concept of a Linux kernel extension denoted User-Monitored Threads (UMT) which tackles this problem. Our extension allows a user-space process to be notified of when the selected threads become blocked or unblocked, making it possible for a runtime to schedule additional work on the idle core. We implemented the extension on the Linux Kernel 5.1 and adapted the Nanos6 runtime of the OmpSs-2 programming model to take advantage of it. The whole prototype was tested on two applications which, on the tested hardware and the appropriate conditions, reported speedups of almost 2x.Comment: 10 pages, 5 figures, conferenc

A Linux Kernel Scheduler Extension for Multi-Core Systems

International audienc

A Linux Kernel scheduler extension for multi-core systems

In this thesis, it is presented a Linux kernel extension that allows a user-space application to be notified of the blocking and unblocking of its threads, making it possible for a core to execute another thread while the other is blocked. The OmpSs Nanos6 runtime is adapted to use this feature