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

Benchmarking LLVM & Clang Against GCC 4.5

Michael Larabel

Published on 21 April 2010
Written by Michael Larabel
Page 6 of 6 - 17 Comments

LLVM-GCC had the best results with Himeno, a Poisson pressure solver, but when Clang was involved, it had the worst numbers. The LLVM-GCC binary produced 60% more MFLOPS than the LLVM Clang version.

Clang had not worked with John The Ripper, but with LLVM-GCC its performance was dismal compared to GCC 4.5.0. The 23-year-old compiler was 60% faster than LLVM-GCC.

Binaries from LLVM-GCC and Clang both struggled to compete with GCC 4.5.0 in the timed HMMer benchmark of a Pfam database search. LLVM-GCC and Clang were about 23% slower.

While using LLVM is faster at building code than GCC (except for the ImageMagick application), in most instances the GCC 4.5 built binaries had performed better than LLVM-GCC or Clang. Clang did deliver a surprising lead over GCC 4.5 and LLVM-GCC with the Apache benchmark where the Clang-built Apache managed to handle 9% more requests per second. There was also significant benefits for LLVM-GCC and Clang with the BYTE Unix Benchmark running the Dhrystone 2 test, but in the rest of the tests the performance was either close to that of GCC or well behind. In some tests, the performance of the Clang generated binaries was simply awful.

Though LLVM / Clang isn't the performance champion at this point, both components continue to be under very active development and there will hopefully be more news to report in the coming months. The LLVM/Clang performance may also certainly improve once more open-source projects begin offering support for detecting and better hooking into Clang. LLVM also does have other advantages over the GNU Compiler Collection that cannot be benchmarked. At the same time though, GCC has the benefits of supporting more hardware targets and hardware optimizations than does LLVM at this point and LLVM also has no plans for supporting Java, Fortran, or some of the other GCC-supported language front-ends. GCC's C++ support is also much more complete than LLVM's Clang at this point.

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. Intel Launches The Core i7 5960X, Mighty Powerful Haswell-E CPUs
  2. AMD Radeon R9 290: Gallium3D vs. Catalyst Drivers
  3. AMD Radeon R9 290 Open-Source Driver Works, But Has A Ways To Go
  4. Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K
Latest Linux Articles
  1. How Intel Graphics On Linux Compare To Open-Source AMD/NVIDIA Drivers
  2. The Fastest NVIDIA GPUs For Open-Source Nouveau With Steam Linux Gaming
  3. Testing For The Latest Linux Kernel Power Regression
  4. The Most Energy Efficient Radeon GPU For AMD Linux Gaming
Latest Linux News
  1. Nouveau X.Org Driver Released With DRI3+Present, Maxwell, GLAMOR
  2. Microsoft & AMD Release C++ AMP Compiler With Linux Support
  3. AMD, Wine & Valve Dominated August For Linux Users
  4. Linux 3.17-rc3 Kernel Released Back On Schedule
  5. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  6. Mesa 10.3 RC2 Arrives Via Its New Release Manager
  7. Ubuntu 14.10's Lack Of X.Org Server 1.16 Gets Blamed On AMD
  8. MSI Motherboard BIOS Updating Remains A Pain For Linux Users
  9. See How Your Linux System Performs Against The Latest Intel/AMD CPUs
  10. AMD Steppe Eagle Flys To Coreboot
Latest Forum Discussions
  1. SSD seems slow
  2. AMD Releases UVD Video Decode Support For R600 GPUs
  3. Is laptop with Intel CPU and AMD dGPU worth buying considering especially AMD Enduro?
  4. Radeon HD5670 and Ubuntu 14.04
  5. Btrfs Gets Talked Up, Googler Encourages You To Try Btrfs
  6. Updated graphics drivers for Ubuntu 12.04 Precise LTS
  7. Catalyst 14.201.1008
  8. It's Now Possible To Play Netflix Natively On Linux Without Wine Plug-Ins