Re: sched regression introduced by NO_NEW_FAIR_SLEEPERS

[drago01]

On Sun, Sep 27, 2009 at 9:50 PM, drago01 <drago01@xxxxxxxxx> wrote:
> On Sun, Sep 27, 2009 at 9:47 PM, drago01 <drago01@xxxxxxxxx> wrote:
>> Hi,
>>
>> Chuck has backported some scheduler patches from 2.6.32 to the fedora kernel.
>>
>> I did the following test to test the new scheduler (cpu is a core i7
>> 920 4 cores + HT).
>>
>> run 8 "md5sum /dev/urandom" task and try to use the desktop (compiz).
>>
>> The result was that moving windows or rotating the cube is very slow.
>> (same happens with pure metacity but is is worse in compiz).
>>
>> Mounting debugfs and doing "echo NEW_FAIR_SLEEPERS > sched_features"
>> results into a useable desktop while the 8 md5sum tasks are running
>> (ie. the system behaves as if they where not running at all from an
>> interactivity pov).
>>
>>
>> P.S: please CC me when replying.
>>
>
> With "NEW_FAIR_SLEEPERS" I can even run 100(!)  "md5sum" task without
> any effect on interactivity. (still have not found a number of tasks
> needed to make the system unresponsive as with 8 with
> "NO_NEW_FAIR_SLEEPERS".

Well ok I can expirence some delays when switching workspaces with 100
tasks but it is still better than 8 with "NO_NEW_FAIR_SLEEPERS"
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