Re: [PATCH] sched: high-res preemption tick

From: Mike Galbraith
Date: Sun Oct 14 2007 - 02:39:03 EST


On Sun, 2007-10-14 at 01:13 +0200, Peter Zijlstra wrote:
> On Sat, 2007-10-13 at 11:17 +0200, Peter Zijlstra wrote:
>
> > > Ah, but HRTICK is not compatible with PREEMPT_RESTRICT, it will be
> > > similar to !WAKEUP_PREEMPT.
> >
> > (I do plan to fix that eventually, just need to do it)
>
> I guess something like this ought to do, but its a tad late so I'm quite
> sure :-)

2.6.23-smp-d-hrt + restrict fix patch
[SUM] 0.0-300.1 sec 176 GBytes 5.03 Gbits/sec
[SUM] 0.0-300.1 sec 175 GBytes 5.02 Gbits/sec
[SUM] 0.0-300.1 sec 176 GBytes 5.05 Gbits/sec

Context switches are further reduced (across the board) over
PREEMPT_RESTRICT, dropping from ~7-8k to ~2.5k with this test, vs ~950
for SCHED_BATCH and ~50k with this tree and no restriction. Throughput
is ~96% of SCHED_BATCH, vs ~55% with no restriction. I see no
interactivity regressions.

-Mike

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