linux-kernel - Re: [PATCH 00/24] Complete EEVDF

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Message-ID: <9cc41a877aa2d263b47de698d3ebe724961f9e55.camel@gmx.de>
Date: Wed, 14 Aug 2024 19:18:08 +0200
From: Mike Galbraith <efault@....de>
To: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Peter Zijlstra <peterz@...radead.org>, mingo@...hat.com, 
 juri.lelli@...hat.com, dietmar.eggemann@....com, rostedt@...dmis.org, 
 bsegall@...gle.com, mgorman@...e.de, vschneid@...hat.com, 
 linux-kernel@...r.kernel.org, kprateek.nayak@....com,
 wuyun.abel@...edance.com,  youssefesmat@...omium.org, tglx@...utronix.de
Subject: Re: [PATCH 00/24] Complete EEVDF

On Wed, 2024-08-14 at 18:59 +0200, Vincent Guittot wrote:
> On Wed, 14 Aug 2024 at 18:46, Mike Galbraith <efault@....de> wrote:
> >
> > On Wed, 2024-08-14 at 16:34 +0200, Vincent Guittot wrote:
> > >
> > > While trying to test what would be the impact of delayed dequeue on
> > > load_avg, I noticed something strange with the running slice. I have a
> > > simple test with 2 always running threads on 1 CPU and the each thread
> > > runs around 100ms continuously before switching to the other one
> > > whereas I was expecting 3ms (the sysctl_sched_base_slice on my system)
> > > between 2 context swicthes
> > >
> > > I'm using your sched/core branch. Is it the correct one ?
> >
> > Hm, building that branch, I see the expected tick granularity (4ms).
>
> On my side tip/sched/core switches every 4ms but Peter's sched/core,
> which is delayed queued on top of tip/sched/core if I don't get it
> wrong, switches every 100ms.

FWIW, I checked my local master-rt tree as well, which has Peter's
latest eevdf series wedged in (plus 4cc290c20a98 now).. it also worked
as expected.

	-Mike