Re: [PATCH] Nick's scheduler policy v7

[Nick Piggin <piggin@cyberone.com.au>]

Martin J. Bligh wrote:

>>I didn't miss 5 revisions, I'll just stick to using my internal
>>numbering for releases.
>>
>>This one has a few changes. Children now get a priority boost
>>on fork, and parents retain more priority after forking a child,
>>however exiting CPU hogs will now penalise parents a bit.
>>
>>Timeslice scaling was tweaked a bit. Oh and remember raising X's
>>priority should _help_ interactivity with this patch, and IMO is
>>not an unreasonable thing to be doing.
>>
>>Please test. I'm not getting enough feedback!
>>
>
>Well, it's actually a bit faster than either mainline or your previous
>rev whilst running SDET:
>
>SDET 128  (see disclaimer)
>                           Throughput    Std. Dev
>              2.6.0-test4       100.0%         0.3%
>         2.6.0-test4-nick       102.9%         0.3%
>       2.6.0-test4-nick7a       105.1%         0.5%
>
>But kernbench is significantly slower. The increase in sys time has 
>dropped from last time, but user time is up.
>
>Kernbench: (make -j vmlinux, maximal tasks)
>                              Elapsed      System        User         CPU
>              2.6.0-test4       45.87      116.92      571.10     1499.00
>         2.6.0-test4-nick       49.37      131.31      611.15     1500.75
>       2.6.0-test4-nick7a       49.48      125.95      617.71     1502.00
>

Thanks Martin. OK, so the drop in kernbench is quite likely to be what
I thought - elevated priorities (caused by eg. make waiting for children)
causing timeslices to shrink. As long as its not a fundamental problem,
this should be able to be tweaked back.

Yeah, I guess the random kernel and user times are probably due to cache.