Re: [RFC PATCH v2 00/17] Core scheduling v2

[Julien Desfossez]

On 08-May-2019 10:30:09 AM, Aaron Lu wrote:
> On Mon, May 06, 2019 at 03:39:37PM -0400, Julien Desfossez wrote:
> > On 29-Apr-2019 11:53:21 AM, Aaron Lu wrote:
> > > This is what I have used to make sure no two unmatched tasks being
> > > scheduled on the same core: (on top of v1, I thinks it's easier to just
> > > show the diff instead of commenting on various places of the patches :-)
> > 
> > We imported this fix in v2 and made some small changes and optimizations
> > (with and without Peterâs fix from https://lkml.org/lkml/2019/4/26/658)
> > and in both cases, the performance problem where the core can end up
> 
> By 'core', do you mean a logical CPU(hyperthread) or the entire core?
No I really meant the entire core.

Iâm sorry, I should have added a little bit more context. This relates
to a performance issue we saw in v1 and discussed here:
https://lore.kernel.org/lkml/20190410150116.GI2490@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#mb9f1f54a99bac468fc5c55b06a9da306ff48e90b

We proposed a fix that solved this, Peter came up with a better one
(https://lkml.org/lkml/2019/4/26/658), but if we add your isolation fix
as posted above, the same problem reappears. Hope this clarifies your
ask.

I hope that we did not miss anything crucial while integrating your fix
on top of v2 + Peterâs fix. The changes are conceptually similar, but we
refactored it slightly to make the logic clear. Please have a look and
let us know

Thanks,

Julien