How to build/optimize for Haswell (AVX2) ?

[tecfreak]

(06-17-2014, 05:11 AM)shuffle2 Wrote: it would be interesting if you posted the same dolphin sources built with normal settings and then with march=haswell. I have a very hard time believing it really "runs smoother".
(but if it's true, I'd like to know why).

I ran the official benchmark to figure out whether disabling HT in the BIOS/EFI settings makes any difference or not.

Here are the results:
@march=native (core-avx2) and O3

HT ON:
12min50sec
http://i.imgur.com/UIDCAxc.jpg

HT OFF:
9min32sec
http://i.imgur.com/k9Ong2p.jpg

A speedup of ~25% !


Bench results with default build settings of same source will follow.

Edit:
You were right. There is absolutely no difference.

@default build settings with HT off
9min35sec
http://i.imgur.com/096BImh.jpg