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. Rosewill RS-MI-01: An Ultra Low-Cost Mini-ITX Chassis
  2. D-Link DCS-2330L HD Wireless Network Camera
  3. Gigabyte AM1M-S2H
  4. AMD's New Athlon/Semprons Give Old Phenom CPUs A Big Run For The Money
Latest Linux Articles
  1. Red Hat Enterprise Linux 7.0 RC Benchmarks
  2. AMD Catalyst 14.4 Brings Few Linux Performance Improvements
  3. The Performance Of Fedora 20 Updated
  4. Clang Fights GCC On AMD's Athlon AM1 APU With Jaguar Cores
Latest Linux News
  1. More Steam Linux Tests/Benchmarks Might Be Coming
  2. NVIDIA's Amazing Single-Board ARM Computer Might Be Delayed
  3. Fedora 21 To Get A Playground, New Features
  4. PC-BSD Is Developing Its Own Desktop Environment
  5. Valve Is Bringing VOGL To Windows & Working On Regression Tests
  6. Canonical Is Taking Over Linux 3.13 Kernel Maintenance
  7. Google Web Designer Is Now Natively Available On Linux
  8. Ubuntu 14.10 Is Codenamed The Utopic Unicorn
  9. Audacious 3.5 Lightweight Audio Player Released
  10. Steam Updated For Ubuntu 14.04 LTS, SteamOS
  11. DNF 0.5 Yum Replacement Now Supports Groups
  12. Red Hat Enterprise Linux 7.0 Is Looking Fantastic
Latest Forum Discussions
  1. HTPC-upgrade advice: AMD Richland A8-7600 or Kaveri A10-6700T ???
  2. The GNOME Foundation Is Running Short On Money
  3. What Else Would You Like To See On Phoronix This Spring?
  4. Linux Kernel Developers Fed Up With Ridiculous Bugs In Systemd
  5. The Most Amazing OpenGL Tech Demo In 64kb
  6. Announcing radeontop, a tool for viewing the GPU usage
  7. New card. Open source drivers only.
  8. Script for Fan Speed Control