Re: 2.6.12-rc6-mm1

Martin J. Bligh
2005-06-11T04:14:56Z

--"Martin J. Bligh" <mbligh@mbligh.org> wrote (on Friday, June 10, 2005 16:50:40 -0700):

>>> 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
>>
>> By the way it has already been decided to remove these patches from -mm
>> pending the completion of current scheduler work. If they turn out to be
>> responsible for this regression I apologise profusely :-|.
>>
>> It is clearer to me now that I have made a mistake with the priority biasing,
>> and the following patch corrects it to the planned behaviour. This is
>> academic at this stage as we won't be looking at this particular feature
>> again in earnest until the other 32 scheduler patches (and any followups) go
>> upstream.
>>
>> It's already known that schedstats data will be off without further code to
>> understand smp nice as well (thanks Nick for pointing out the data)... more
>> academic stuff but obviously something to consider when/if we get there.
>
> OK, I backed out those 4, and the degredation mostly went away.
> See http://ftp.kernel.org/pub/linux/kernel/people/mbligh/abat/perf/kernbench.moe.png
>
> and more specifically, see the +p5150 near the right hand side.
> I don't think it's quite as good as mainline, but much closer.
> I did this run with HZ=1000, and the the one with no scheduler
> patches at all with HZ=250, so I'll try to do a run that's more
> directly comparable as well

OK, that makes it look much more like mainline. Looks like you were still
revising the details of your patch Con ... once you're ready, drop me a
URL for it, and I'll make the system whack on that too.

M.

PS. Hmmm. I need to get better at identifying what +p5150 means in the
graphs, etc ;-( Maybe HTML explanation with embedded png image.