freevec.org

Lately, I've been receiving some emails about the project being dead. I understand it's been a while since my last post, and no release has been done in a long time -and the last one (1.0.4) is offline -because it has bugs and I was unable to fix them at the time.

The reason is that I've been working on libfreevec v2. This one is a complete rewrite, supporting all 3 of the major SIMD engines (SSE, AltiVec, ARM NEON). It will take a while to develop but it will get there. Of course, due to my current job at Genesi USA, and my current work on a new Debian port for arm (armhf), priority will be given to the ARM NEON port, then AltiVec and finally SSE, time permitting.

Konstantinos Margaritis

Here's the link to the announcement:

http://lists.fixstars.com/pipermail/yellowdog-announce/2009-June/000214.html

From the press release:

I'm in the process of rewriting libfreevec and porting it to other SIMD platforms, apart from AltiVec (which I consider dead or dying, unfortunately, thanks to the Big Powers that decided it's no longer important along with PowerPC, but that should be another topic). Anyway, the main platforms chosen are AltiVec (of course :), SSE (SSE2, SSE3 and possiby SSE4), ARM NEON and Cell SPU.

While completing Eigen2 AltiVec support (should be almost complete now), I noticed that the 32-bit integer multiplication didn't work correctly all of the time. As AltiVec does not really include any instruction to do 32-bit integer multiplication, I used Apple's routine from the Apple Developer's site. But this didn't work and some results were totally off. With some debugging, I found out that this routine works for unsigned 32-bit integers, where Eigen2 uses signed integers! So, I had to search more, and to my surprise, I found no reference of any similar work. So I had 2 choices: a) ditch AltiVec integer vectorisation from Eigen2 (not acceptable!) b) implement my own method! It is obvious which choice I followed :)
UPDATE: Thanks to Matt Sealey, who noticed I could have used vec_abs() instead of vec_sub() and vec_max(). Duh! :D

Hello again,

I managed to find time to update all of the libfreevec benchmarks to the latest version 1.0.4 and also include more complete tests and added a non-ppc architecture (an Athlon X2 5000 @2.6Ghz) where the same tests were run (as 32-bit apps on a 64-bit Linux) for comparison. This is important for two reasons:

• to find how PowerPC CPUs compare to a current popular x86 CPU (the same benchmarks will be done on an Intel CPU soon)
• to find any deficiencies in glibc itself (as you will see there are many).

All benchmarks were run on OpenSuse 11.0, except for the G5 which uses Debian Lenny/testing. The compiler used was gcc 4.3.2. All functions have been tested to work correctly on each platform.