Re: [PATCH 4/4] numa: introduce numa cling feature

[王贇 <yun.wang@linux.alibaba.com>]

On 2019/7/12 下午4:58, 王贇 wrote:
[snip]
> 
> I see, we should not override the decision of select_idle_sibling().
> 
> Actually the original design we try to achieve is:
> 
>   let wake affine select the target
>   try find idle sibling of target
>   if got one
> 	pick it
>   else if task cling to prev
> 	pick prev
> 
> That is to consider wake affine superior to numa cling.
> 
> But after rethinking maybe this is not necessary, since numa cling is
> also some kind of strong wake affine hint, actually maybe even a better
> one to filter out the bad cases.
> 
> I'll try change @target instead and give a retest then.

We now leave select_idle_sibling() untouched, instead prevent numa swap
with task cling to dst, and stop wake affine when curr & prev cpu are on
different node and wakee cling to prev.

Retesting show a even better results, benchmark like dbench also show 1%~5%
improvement, not stable but always improved now :-)

Regards,
Michael Wang

> 
> Regards,
> Michael Wang
>