Effect of SMS register move scheduling

Revital Eres revital.eres at linaro.org
Thu Aug 25 10:17:29 UTC 2011


>> Yes, I also noticed that. When I tested it only one reg-move was
>> created so the scheduling patch would not effect on it.
> FWIW, looking at the results I posted yesterday, the scheduling patch
> did improve the results compared with the non-scheduling patch:

You are right! this was my mistake, sorry about that...

>    mjpegenc
>      before:  500000 runs take 28.6987s
>      after:   500000 runs take 7.31342s
>      speedup: x3.92
> That single register move wasn't schedulable within the current ii,
> so the patch used a higher ii without the move.  Unfortunately,
> while the new loop needs fewer spills, it doesn't avoid them completely.

Right, this can also be seen in the results you posted today
evaluating the effect of SMS on the vectorized code.


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