A new version of the OpenMP standard, 5.0, was released in November 2018 and brings several new constructs to the users. OpenMP is an API consisting of compiler directives and library routines for high-level parallelism in C, C++, and Fortran programs. The upcoming version of GCC adds support for some parts of this newest version of the standard.
This article highlights some of the latest features, changes, and “gotchas” to look for in the OpenMP standard.
Continue reading “What’s new in OpenMP 5.0”
You’ve probably been taught that picking an algorithm that has the best Big-O asymptotic cost will yield the best performance. You might be surprised to find that on current hardware, this isn’t always the case. Much of algorithmic analysis assumes very simple costs where the order of operations doesn’t matter. Memory access times are assumed to be the same. However, the difference between a cache hit (a few processor clock cycles) and a cache miss that requires access to main memory (a couple hundred cycles) is immense.
This article series is the result of the authors (William Cohen and Ben Woodard) discussion that there is a disconnect on the typical ideas of algorithm efficiency taught in computer science and computer engineering versus what is currently encountered in actual computer systems.
Continue reading “Algorithms != Programs and Programs are not “One size fits all””
Diving into XDP
In the first part of this series on XDP, I introduced XDP and discussed the simplest possible example. Let’s now try to do something less trivial, exploring some more-advanced eBPF features—maps—and some common pitfalls.
XDP is available in Red Hat Enterprise Linux 8, which you can download and run now.
Continue reading “Using eXpress Data Path (XDP) maps in RHEL 8: Part 2”
XDP: From zero to 14 Mpps
In past years, the kernel community has been using different approaches in the quest for ever-increasing networking performance. While improvements have been measurable in several areas, a new wave of architecture-related security issues and related counter-measures has undone most of the gains, and purely in-kernel solutions for some packet-processing intensive workloads still lag behind the bypass solution, namely Data Plane Development Kit (DPDK), by almost an order of magnitude.
But the kernel community never sleeps (almost literally) and the holy grail of kernel-based networking performance has been found under the name of XDP: the eXpress Data Path. XDP is available in Red Hat Enterprise Linux 8, which you can download and run now.
Continue reading “Achieving high-performance, low-latency networking with XDP: Part I”
In this article, I want to provide some background details about our recently developed demonstration video – “Running Game of Life across multiple architectures with Red Hat Enterprise Linux“.
This video shows the Game of Life running in a heterogeneous environment using three 64-bit hardware architectures: aarch64 (ARM v8-A), ppc64le (IBM Power little endian) and x86_64 (Intel Xeon). If you are not familiar with the rules of this cellular automaton, they are worth checking out via the reference above.
Continue reading “Running HPC workloads across multiple architectures with Red Hat Enterprise Linux”