mersenneforum.org

mersenneforum.org (https://www.mersenneforum.org/index.php)
-   Information & Answers (https://www.mersenneforum.org/forumdisplay.php?f=38)
-   -   Support AVX (https://www.mersenneforum.org/showthread.php?t=15732)

Unregistered 2011-07-04 11:46

Support AVX
 
Support the next version of Prime95 AVX? If yes, is already known when this version is available?

Prime95 2011-07-04 13:24

Yes to AVX. No as to a known date.

At present, FFT sizes 32, 128, 512, and 2048 are coded and mostly working.

henryzz 2011-07-04 16:57

[QUOTE=Prime95;265389]Yes to AVX. No as to a known date.

At present, FFT sizes 32, 128, 512, and 2048 are coded and mostly working.[/QUOTE]
Any hints as to speed increase on these FFTs?

Prime95 2011-07-04 18:02

Just got numbers for the 2K FFT:

SSE2: 100 iters in 1.110 ms
AVX: 100 iters in 0.682 ms

I'm not sure if these numbers will extrapolate to large FFTs. These small FFTs operate completely in the L1 cache.

henryzz 2011-07-04 19:11

[QUOTE=Prime95;265412]Just got numbers for the 2K FFT:

SSE2: 100 iters in 1.110 ms
AVX: 100 iters in 0.682 ms

I'm not sure if these numbers will extrapolate to large FFTs. These small FFTs operate completely in the L1 cache.[/QUOTE]
Nice. I use the smaller FFTs most of the time in LLR anyway so I am not too worried.:smile:

ixfd64 2011-07-05 17:12

[QUOTE=Prime95;265412]Just got numbers for the 2K FFT:

SSE2: 100 iters in 1.110 ms
AVX: 100 iters in 0.682 ms[/QUOTE]

These timings seem consistent with the fact that AVX is not twice as fast as SSE2 despite the increase to 256 bits. Hopefully AVX2 and the new Tri-Gate chips will "fix" this.


All times are UTC. The time now is 10:37.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.