Software Archives
Benchmarking Retpoline-Enabled GCC 8 With -mindirect-branch=thunk

We have looked several times already at the performance impact of Retpoline support in the Linux kernel, but what about building user-space packages with -mindirect-branch=thunk? Here is the performance cost to building some performance tests in user-space with -mindirect-branch=thunk and -mindirect-branch=thunk-inline.

16 January 2018 - 5 Comments
Benchmarking Ubuntu's Low-Latency Kernel & Liquorix Post-Meltdown

A new Phoronix Premium member was hypothesizing in the forums whether Ubuntu's low-latency kernel would be performing better in the wake of the Kernel Page Table Isolation (KPTI) support in the kernel for fending off the Meltdown CPU vulnerability. With always aiming to deliver on test requests by premium members, I ran some benchmarks of the Ubuntu low-latency vs. generic kernels and I also tossed in the Liquorix kernel for benchmarking too.

14 January 2018 - 30 Comments
GCC 8.0 vs. LLVM Clang 6.0 On AMD EPYC

At the beginning of January I posted some early LLVM Clang 6.0 benchmarks on AMD EPYC while in this article is comparing the tentative Clang 6.0 performance to that of the in-development GCC 8.0. Both compilers are now into their feature freeze and this testing looked at the performance of generated binaries both for generic x86_64 as well as being tuned for AMD's Zen "znver1" microarchitecture.

13 January 2018 - 10 Comments
KPTI + Retpoline Linux Benchmarking On Old Laptops

Over the past week and a half of running many benchmarks looking at the performance impact of the Linux KPTI and Retpoline patches for Spectre and Meltdown mitigation, one of the most common test requests is some thorough benchmarks on older systems. Why that's important is with older (pre-Westmere) CPUs there isn't PCID (Process Context Identifier) support that's used by KPTI, which helps offset some of the performance loss. So for some test results to share today are two old ThinkPads from the Clarksfield and Penryn days compared to a newer Broadwell ThinkPad in looking at the performance difference.

11 January 2018 - 34 Comments
Benchmarking Linux With The Retpoline Patches For Spectre

While the Kernel Page Table Isolation (KPTI) patches were quick to land in the mainline Linux kernel for addressing the Meltdown CPU vulnerability, the "Retpoline" patches are still being worked on as the leading approach on the Linux side for dealing with the Spectre CPU vulnerability. The Retpoline patches are said to have little impact on performance, but here are our benchmarks of these kernel patches for seeing how they affect a variety of AMD and Intel systems.

8 January 2018 - 58 Comments
Linux KPTI Tests Using Linux 4.14 vs. 4.9 vs. 4.4

Yet another one of the avenues we have been exploring with our Linux Page Table Isolation (KPTI) testing has been looking at any impact of this security feature in the wake of the Meltdown vulnerability when testing with an older Linux Long Term Support (LTS) release. In particular, when using a kernel prior to the PCID (Process Context Identifier) support in the Linux kernel that is used to lessen the impact of KPTI.

4 January 2018 - 30 Comments
Initial Benchmarks Of The Performance Impact Resulting From Linux's x86 Security Changes

Over the past day you've likely heard lots of hysteria about a yet-to-be-fully-disclosed vulnerability that appears to affect at least several generations of Intel CPUs and affects not only Linux but also Windows and macOS. The Intel CPU issue comes down to leaking information about the kernel memory to user-space, but the full scope isn't public yet until the bug's embargo, but it's expected to be a doozy in the data center / cloud deployments. Due to the amount of interest in this issue, here are benchmarks of a patched kernel showing the performance impact of the page table isolation patches.

2 January 2018 - Add A Comment
LLVM Clang 6.0 Benchmarks On AMD's EPYC Yield Some Performance Benefits

With LLVM 6.0 being branched this week and that marking the end of feature development on this next compiler update before its stable debut in February, here are some benchmarks of the very latest LLVM Clang 6.0 compiler on AMD's EPYC 7601 32-core / 64-thread processor as we see how well the AMD Zen "znver1" tuning is working out.

2 January 2018 - 3 Comments
KVM Smokes VirtualBox On Initial AMD EPYC Linux Tests

I've been working on some AMD EPYC virtualization tests on and off the past few weeks. For your viewing before ending out the year are some initial VirtualBox vs. Linux KVM benchmarks for seeing how the guest VM performance compares.

30 December 2017 - 23 Comments
Running OpenCL On The CPU With POCL 1.0, Xeon & EPYC Testing

This week marked the release of the long-awaited POCL 1.0 release candidate. For the uninformed POCL, or the Portable Computing Language, is a portable implementation of OpenCL 1.2~2.0 that can run on CPUs with its LLVM code generation and has also seen back-ends for its OpenCL implementation atop AMD HSA and even NVIDIA CUDA. I've been trying out POCL 1.0-RC1 on various Intel and AMD CPUs.

7 December 2017 - 18 Comments
The New Features Of Linux 4.15: AMDGPU DC, RISC-V, EPYC Benefits, VR Improvements

The merge window is effectively over for Linux 4.15 with it being the 14th day of the process, although 4.15-rc1 might not end up coming out today due to Linus Torvalds' traveling around the US Thanksgiving holiday. But with Torvalds tending to not approve major last minute additions to new kernels, we don't anticipate any last minute surprises and therefore here is our feature overview of the changes and new features of Linux 4.15. This is arguably the most exciting and feature-packed kernel update ever.

26 November 2017 - 12 Comments
Benchmarks Show Firefox 57 Quantum Doing Well, But Chrome Largely Winning

With the hype this week around Firefox Quantum Beta with its user-interface refinements and more noticeably the performance improvements, I decided to run some benchmarks on my end with a variety of tests comparing Firefox 52 ESR, Firefox 56 stable, Firefox 57 Quantum beta, and Chrome 60. Here are those web browser benchmark results from the Linux x86-64 desktop.

28 September 2017 - 90 Comments
GCC & LLVM Clang Compiler Benchmarks On AMD's EPYC 7601

For squeezing maximum performance out of Linux systems with source-based workloads, most of you know there can often be tweaks to be had to the compiler stack for greater performance. As well with the never-ending advancements to the leading open-source code compilers, between releases can be measurable performance benefits but sometimes not without regressions too. With AMD's EPYC line-up still being very fresh and the underlying Zen microarchitecture (or "znver1" as referred to by the compiler toolchains), here are a variety of benchmarks under recent releases of the GCC and LLVM Clang compilers.

26 September 2017 - 17 Comments
How AMD EPYC & Intel Xeon Gold Compare To Various Amazon EC2 Cloud Instances

Last week we began with our EPYC 7601 Linux benchmarking of this high-end AMD server CPU featuring 32 cores / 64 threads per socket. Earlier this week were also some 10-year old Opteron vs. EPYC benchmarks and power efficiency tests while the latest in our EPYC Linux testing is seeing how the new AMD processor compares to various Amazon EC2 cloud instances.

20 September 2017 - 13 Comments
The Exciting Features Of Linux 4.14: Zstd, Vega Hugepages, AMD SME, New Drivers

With Linux 4.14-rc1 having been released one day early, here is our look at the new features of Linux 4.14 with the merge window having been closed. There's a lot to get excited about with Linux 4.14 from graphics driver improvements, new hardware improvements, a new Realtek WiFi driver, a PWM vibrator driver, and Btrfs Zstd compression support..

17 September 2017 - 7 Comments
A Look At The New Features Of GNOME 3.26

With GNOME 3.26 due to be officially released on Wednesday, 13 September, here is a look at the new features to be found in this major desktop update and screenshots from testing the latest GNOME 3.26 packages via Fedora 27's development images.

10 September 2017 - 114 Comments
Power Use, RAM + Boot Times With Unity, Xfce, GNOME, LXDE, Budgie & KDE Plasma

One of the first follow-on requests from this morning's Razer Blade Stealth Linux testing was for on top of all the other data-sets shared in that article to also look at the RAM usage, battery power draw, and boot times for the different desktop options on Ubuntu 17.04. As the request came in from a Phoronix Premium supporter, I jumped on that and here are some of those numbers.

30 August 2017 - 137 Comments
OpenGL 4.6 Released With Vulkan/SPIR-V Ingestion, Parallel Shader Compiles & Finally AF

As we have been anticipating for weeks/months, a new formal update to OpenGL has been in the works and it's officially out today. Meet OpenGL 4.6! This is a pretty significant update and internally they had the debate whether to call it OpenGL 5.0, but here we are with OpenGL 4.6 that features Vulkan/SPIR-V extensions and more. The good news is the open-source Mesa drivers aren't too far out from OpenGL 4.6 support, at least RadeonSI and Intel.

31 July 2017 - 25 Comments
Ryzen Compiler Performance: Clang 4/5 vs. GCC 6/7/8 Benchmarks

A few days back I posted some fresh AMD Ryzen compiler benchmarks of LLVM Clang now that it has its new Znver1 scheduler model, which helps out the performance of Ryzen on Linux with some of the generated binaries tested. But it was found still that Haswell-tuned binaries are sometimes still faster on Ryzen than the Zen "znver1" tuning itself. For continuing our fresh compiler benchmarks from AMD's new Ryzen platform, here are the latest GCC numbers.

23 July 2017 - 21 Comments
Benchmarking LLVM/Clang's New AMD Zen Scheduler Model

Just prior to LLVM 5.0 being branched yesterday, the AMD Zen scheduler model finally landed in LLVM and has the potential of boosting the performance of generated binaries targeting AMD's Zen "znver1" architecture. Here are some benchmarks of LLVM Clang 4.0 compared to the latest LLVM Clang compiler code when testing with both generic x86-64 optimizations and then optimized builds for the first-generation Zen CPUs, tested on a Ryzen 7 processor.

20 July 2017 - 7 Comments
AMD Ryzen AOCC 1.0 Compiler Tuning Benchmarks

On Friday I posted some benchmarks of AMD's new AOCC code compiler for Ryzen compared to LLVM Clang 4.0/5.0 and GCC 6/7/8. The AOCC 1.0 benchmarks on Ryzen 7 didn't offer much over LLVM Clang for which this "AMD Optimizing C/C++ Compiler" is based, but in this article are some tuning benchmarks.

21 May 2017 - 25 Comments

577 software articles published on Phoronix.