Re: EEVDF and NUMA balancing

Peter Zijlstra
2023-10-04T12:06:02Z

On Wed, Oct 04, 2023 at 02:01:26PM +0200, Julia Lawall wrote:
>
>
> On Tue, 3 Oct 2023, Peter Zijlstra wrote:
>
> > On Tue, Oct 03, 2023 at 10:25:08PM +0200, Julia Lawall wrote:
> > > Is it expected that the commit e8f331bcc270 should have an impact on the
> > > frequency of NUMA balancing?
> >
> > Definitely not expected. The only effect of that commit was supposed to
> > be the runqueue order of tasks. I'll go stare at it in the morning --
> > definitely too late for critical thinking atm.
>
> Maybe it's just randomly making a bad situation worse rather than directly
> introduing a problem. There is a high standard deviatind in the
> performance. Here are some results with hyperfine. The general trends
> are reproducible.

OK,. I'm still busy trying to bring a 4 socket machine up-to-date...
gawd I hate the boot times on those machines :/

But yeah, I was thinking similar things, I really can't spot an obvious
fail in that commit.

I'll go have a poke once the darn machine is willing to submit :-)