Re: [REPORT] cfs-v4 vs sd-0.44

Jan Engelhardt
2007-04-21T17:40:53Z

On Apr 21 2007 18:00, Ingo Molnar wrote:
>* Con Kolivas <kernel@kolivas.org> wrote:
>
>> > Feels even better, mouse movements are very smooth even under high
>> > load. I noticed that X gets reniced to -19 with this scheduler.
>> > I've not looked at the code yet but this looked suspicious to me.
>> > I've reniced it to 0 and it did not change any behaviour. Still
>> > very good.
>>
>> Looks like this code does it:
>>
>> +int sysctl_sched_privileged_nice_level __read_mostly = -19;
>
>correct. Note that Willy reniced X back to 0 so it had no relevance on
>his test. Also note that i pointed this change out in the -v4 CFS
>announcement:
>
>|| Changes since -v3:
>||
>|| - usability fix: automatic renicing of kernel threads such as
>|| keventd, OOM tasks and tasks doing privileged hardware access
>|| (such as Xorg).
>
>i've attached it below in a standalone form, feel free to put it into
>SD! :)

Assume X went crazy (lacking any statistics, I make the unproven
statement that this happens more often than kthreads going berserk),
then having it niced with minus something is not too nice.

Jan
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