1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

Mozilla Spots Massive Performance Regression In GCC

Compiler

Published on 25 June 2010 10:16 AM EDT
Written by Michael Larabel in Compiler
10 Comments

Mozilla developers on the GCC mailing list have been expressing what they describe as a "massive performance regression" and "what might be the biggest compiler-upgrade-related performance difference we've seen at Mozilla." The Mozilla developers have upgraded from GCC 4.3 to GCC 4.5, which was released in April, and now they are experiencing massive slowdowns.

Taras Glek of Mozilla reports that with this newest release of the GNU Compiler Collection they are experiencing 4-19% slowdowns on average with their automated benchmarks on their 32-bit and 64-bit Linux builds. The only case where there wasn't a slowdown was with the 64-bit SunSpider JavaScript benchmark where it sped up by 8% when being built under GCC 4.5. Some of these Mozilla slowdowns after the GCC upgrade are discussed here and here. The start of the mailing list discussion can be found here.

Because of these performance shortcomings on GCC 4.5, Mozilla is reconsidering their switch to this newest compiler release. At least because Mozilla has an automated benchmarking infrastructure in place, they were able to spot this issue timely themselves rather than waiting for us or others to spot the problem.

Initial thoughts on these major regressions caused by GCC are the Mozilla developers building Firefox with flags for size optimizations rather than speed and possible regressions from code inlining. Mozilla was originally switching to GCC 4.5 due to its newly-introduced plug-in support and the ability to build Firefox with PGO (Profile-Guided Optimizations).

Following the release of GCC 4.5.0 in mid-April we published our own GCC 4.5 benchmarks and GCC vs. Clang/LLVM benchmarks.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. AMD Launches New FX CPUs, Cuts Prices On Existing Processors
  2. Preview: AMD's FX-9590 Eight-Core At Up To 5.0GHz On Linux
  3. Intel Launches The Core i7 5960X, Mighty Powerful Haswell-E CPUs
  4. AMD Radeon R9 290: Gallium3D vs. Catalyst Drivers
Latest Linux Articles
  1. Ondemand vs. Performance CPU Governing For AMD FX CPUs On Linux 3.17
  2. How Intel Graphics On Linux Compare To Open-Source AMD/NVIDIA Drivers
  3. The Fastest NVIDIA GPUs For Open-Source Nouveau With Steam Linux Gaming
  4. Testing For The Latest Linux Kernel Power Regression
Latest Linux News
  1. Borderlands 2 Is Coming To Linux
  2. The Witcher 2 Ups The Performance More & Works Around Catalyst Bug
  3. Running Gallium3D's LLVMpipe On The Eight-Core 5GHz CPU
  4. Trying Intel OpenCL On Linux For Video Encoding
  5. GSoC 2014 Yielded Some Improvements For Mesa/X.Org This Year
  6. webOS Lives On As LuneOS With New Release
  7. Marek Lands Radeon Gallium3D HyperZ Improvements
  8. Mozilla Firefox 32 Surfaces With HTML5, Developer Changes
  9. Nouveau X.Org Driver Released With DRI3+Present, Maxwell, GLAMOR
  10. Microsoft & AMD Release C++ AMP Compiler With Linux Support
Latest Forum Discussions
  1. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  2. nv and xorg.conf under Debian PPC
  3. AMD graphics doesn't work with AMD Catalyst drivers
  4. Best Radeon for a Power Mac G5?
  5. The dangers of Linux kernel development
  6. Updated and Optimized Ubuntu Free Graphics Drivers
  7. AMD Releases UVD Video Decode Support For R600 GPUs
  8. SSD seems slow