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 The SLP Vectorizer On LLVM Clang 3.4

Compiler

Published on 29 July 2013 03:24 PM EDT
Written by Michael Larabel in Compiler
Comment On This Article

Following word this weekend that Apple and Google engineers agree on SLP vectorization by default for the LLVM/Clang compiler, I carried out some fresh SLP Vectorizer benchmarks this weekend from the LLVM Clang 3.4 SVN development code.

The SLP Vectorizer can vectorize memory access, arithmetic operations, comparison operations, and other select operations. Back when it was ready in LLVM Clang 3.3 I did some early benchmarks and explained it in more detail. There's also the LLVM auto-vectorizer documentation.

With LLVM Clang 3.4 SVN it looks like the superword-level parallelism vectorizer will at least be enabled for the -O3 optimization level if not for other optimization levels too. With this upcoming change, from the LLVM/Clang Subversion code as of this weekend I ran some benchmarks when comparing the -fslp-vectorize compiler switch for a range of C/C++ benchmarks. The -O3 -march=native compiler switches were set the entire time.

These test results can be found on OpenBenchmarking.org in 1307291-SO-FSLPVECTO83.


For most of our real-world workload tests on Linux with LLVM/Clang 3.4 SVN, there was little change in performance out of the basic SLP Vectorizer. However, as the benchmarks showed this past weekend, for certain operations and micro-benchmarks there are worthwhile improvements to find with this straight-code vectorizer. There's at least no regressions even though this isn't quite as useful as the Loop Vectorizer.

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. Even With Re-Clocking, Nouveau Remains Behind NVIDIA's Proprietary Linux Driver
  2. The Power Consumption & Efficiency Of Open-Source GPU Drivers
  3. AMD R600g/RadeonSI Performance On Linux 3.16 With Mesa 10.3-devel
  4. Intel Pentium G3258 On Linux
Latest Linux Articles
  1. Nouveau vs. Radeon vs. Intel Tests On Linux 3.16, Mesa 10.3-devel
  2. KVM Benchmarks On Ubuntu 14.10
  3. X.Org Server 1.16 Officially Released With Terrific Features
  4. Ubuntu With Linux 3.16 Smashes OS X 10.9.4 On The MacBook Air
Latest Linux News
  1. The FFmpeg vs. Libav War Continues In Debian Land
  2. Grand Theft Auto Running On Direct3D Natively On Linux Shows Gallium3D Potential
  3. GCC As A Just-In Time Compiler Is An Interesting Project
  4. Age Of Wonders III Is Still Being Ported To Linux
  5. Git 2.1 To Further Mainline Windows Support Patches
  6. Debian 8.0 Jessie Is Settling For Linux 3.16
  7. Meson: A Next-Gen Build System Showing Promise
  8. Linux 3.16-rc7 Calms Things Down For The Linux 3.16 Kernel
  9. Open-Source AMD Users Report Hawaii GPU Acceleration Is Working
  10. Linus Torvalds On GCC 4.9: Pure & Utter Crap
Latest Forum Discussions
  1. List of Linux friendly Kickstarter projects
  2. Updated and Optimized Ubuntu Free Graphics Drivers
  3. Linus Torvalds On GCC 4.9: Pure & Utter Crap
  4. Porting Mesa to the Playstation 2
  5. ASRock AM1H-ITX: One Of The Best AM1 Mini-ITX Motherboards
  6. Debian + radeonsi
  7. Open-source drivers on ATI R7 260X
  8. Table test