Monthly Archives: May 2009

Last Performance Smackdown For Awhile

This is getting arduous. I think this will be my last performance smackdown for awhile. First off, I put the latest in the icc 10.1 series — 10.1.022 — into FATE for both x86_32 and x86_64. It seems to work quite well with the 32-bit version having a little trouble with the regression suite; 64-bit version passes all of our tests.

For this test, I decided to use a much shorter video. The file in question has ~10700 frames of MPEG-4 part 2 video at 704×400, along with MP3 audio. The x86_32 performance trend shapes up precisely as we have seen in previous tests, and with a file that takes 1/10 the time to decode. FFmpeg SVN revision is 18737.


32-bit performance comparison, 2009-05-04

As usual, all handcrafted ASM optimizations are disabled. The x86_32 configurations were built with –march/–cpu equal to core2 where available, else pentium4 where available.

Here is the 64-bit chart. It must be noted that FFmpeg compiled with 11.0.083 did not decode the file correctly.


64-bit performance comparison, 2009-05-04

Update: I finally got the dark horse contender — LLVM — to compile at SVN 70961 for x86_64. Out of 2 runs with this same file, it posts a best time of 33.6 seconds.

The differences look severe, but they are actually within a few seconds of each other. And notice that all 64-bit configurations are demonstrably speedier than all 32-bit configurations.

Somehow, it’s only now as I prepare to publish this entry that I realize something amiss– how did my current gcc-svn build manage to build FFmpeg when FATE can’t do the same? It must be the configure options.

See Also:

Latest Compiler News

I’ve been doing compiler stuff tonight:

  • Thanks to Carl Eugen Hoyos as well as my compiler contact inside Intel for advising me on how to procure icc version 11.0.083 (vs. .081 previously) along with an unlimited, non-commercial compiler license. Looks like I won’t have to worry about the 31-day limit now (though there might still be a problem with the Mac OS X version). Further, the 32-bit compiler runs from the 64-bit kernel prompt (I am trying to move away from the 32-bit chroot setup and am meeting with some success). Both 32- and 64-bit versions are now in FATE.
  • After a brief respite following the release of gcc 4.4.0, I have updated the gcc SVN snapshots and reinstated the configurations tracking the FFmpeg build status on experimental gcc 4.5 builds. I’m especially proud, though, that I managed to build one C compiler binary that runs under 64-bit Linux but can build both 32- and 64-bit binaries.
  • A lot of people wonder about this, so I wanted to make it known that I have been briefed on how to use LLVM, the rising star of compiler technology. Thus far, I have not been able to create a build that compiles FFmpeg. I hear that they’re working on it.

New performance smackdowns to come, at least for those that can currently build FFmpeg (the current rev of gcc 4.5-SVN, rev 147090, isn’t doing so well– failing across platforms).