Re: 2.6.12-rc6-mm1

Con Kolivas
2005-06-10T12:04:47Z

On Fri, 10 Jun 2005 17:02, Ingo Molnar wrote:
> * Martin J. Bligh <mbligh@mbligh.org> wrote:
> > > I'm assuming it was the CPU scheduler patches. There are 36 of them ;)
> >
> > Backed them all out ... performance thunks down to earth again, and is
> > actually the best I've seen it ever (probably 250Hz is helping, I used
> > to run 100 in -mjb for better benefit).
> >
> > the +5081 item is the one to look at
> > http://ftp.kernel.org/pub/linux/kernel/people/mbligh/abat/perf/kernbench.
> >moe.png
> >
> > Patch I used was here:
> >
> > http://ftp.kernel.org/pub/linux/kernel/people/mbligh/abat/patches/nosched
> >
> > But it was just everything under the "CPU scheduler" section of your
> > series file.
>
> we know from Nick's testing that the patches up to and including
> dynamic-sched-domains-ia64-changes.patch are probably OK. So the
> candidates for the regression are:
>
> sched-implement-nice-support-across-physical-cpus-on-smp.patch
> sched-change_prio_bias_only_if_queued.patch
> sched-account_rt_tasks_in_prio_bias.patch
> consolidate-preempt-options-into-kernel-kconfigpreempt.patch
> enable-preempt_bkl-on-preemptsmp-too.patch
> sched-tweak-idle-thread-setup-semantics.patch
> sched-voluntary-kernel-preemption.patch
> sched-smp-nice-bias-busy-queues-on-idle-rebalance.patch
> sched-task_noninteractive.patch
> sched-run-sched_normal-tasks-with-real-time-tasks-on-smt-siblings.patch
>
> there are two feature patches in this:
>
> enable-preempt_bkl-on-preemptsmp-too.patch
> sched-voluntary-kernel-preemption.patch
>
> so make sure you have PREEMPT_BKL and PREEMPT_VOLUNTARY disabled.
>
> these ones should not impact your workload's functionality (unless they
> are buggy):
>
> sched-account_rt_tasks_in_prio_bias.patch
> consolidate-preempt-options-into-kernel-kconfigpreempt.patch
> sched-tweak-idle-thread-setup-semantics.patch
> sched-run-sched_normal-tasks-with-real-time-tasks-on-smt-siblings.patch
>
> and unless you are using separate nice levels, this one shouldnt make a
> difference in theory:
>
> sched-implement-nice-support-across-physical-cpus-on-smp.patch
>
> which leaves the following 3 likely candidates:
>
> sched-change_prio_bias_only_if_queued.patch
> sched-smp-nice-bias-busy-queues-on-idle-rebalance.patch

These tend to run together so just try adding my four patches together. In
retrospect I guess they're likely candidates because they also change the
_ratio_ of balance which they should not so they are buggy as a group
currently. Easy enough to fix but it will make it easy to pinpoint the
problem if they're responsible.

sched-implement-nice-support-across-physical-cpus-on-smp.patch
sched-change_prio_bias_only_if_queued.patch
sched-account_rt_tasks_in_prio_bias.patch
sched-smp-nice-bias-busy-queues-on-idle-rebalance.patch

Con