Re: [revert] mysql+oltp regression

From: Ingo Molnar
Date: Mon Aug 11 2008 - 09:31:59 EST



* Gregory Haskins <ghaskins@xxxxxxxxxx> wrote:

> Gregory Haskins wrote:
>> Ingo Molnar wrote:
>>> * Gregory Haskins <ghaskins@xxxxxxxxxx> wrote:
>>>
>>>
>>>>>> Speaking of this: Another patch I submitted to you Ingo (had to
>>>>>> do with updating the load_weight inside task_setprio) seems to
>>>>>> also have this phenomenon: e.g. its technically correct but
>>>>>> further testing has revealed negative repercussions elsewhere.
>>>>>> So please ignore that patch (or revert if you already pulled
>>>>>> in, but I don't think you have). Ill try to look into this
>>>>>> issue as well.
>>>>>>
>>>>> ok, under which thread/subject is that? Not queued in tip/sched/*
>>>>> yet, correct?
>>>>>
>>>> Here is the original thread:
>>>>
>>>> http://lkml.org/lkml/2008/7/3/416
>>>>
>>>> I do not believe you have queued it anywhere (public anyway) yet.
>>>>
>>>> Note I have already invalidated 1/2, and now I am retracting 2/2 as
>>>> well. (1/2 is actually a bogus patch, 2/2 is "technically correct"
>>>> but causes ripples in the load balancer that need to be sorted out
>>>> first.
>>>>
>>>
>>> ok, thanks. I'm curious, what are those ripple effects? Stability or
>>> performance?
>>>
>>
>> Performance. I found it while working on my pi series (which fyi I
>> should have a v2 refresh for soon, probably today...i am hoping to get
>> some review feedback from you on that as well, time permitting of
>> course ;).
>>
>> Basically the behavior I was observing was that kernel builds via
>> distcc would cluster all the cc1 jobs on a single core. At first I
>> thought my pi-series was screwed up, but then I realized I had applied
>> the patch referenced above earlier in my development tree, and
>> removing it allowed pi to work fine.
>>
>> I found the problem with in once boot cycle with ftrace (thanks Steve!).
>
> Hmm..Im not sure what went wrong between brain and hand above, but of
> course I meant to say ".. within one boot cycle ..", not "with in
> once". Heh.

my second reading of that sentence auto-corrected it to your intented
version ;-)

Ingo
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