Re: [CFT][PATCH] new scheduler policy

[Mike Galbraith]

At 11:40 PM 8/19/2003 +1000, Nick Piggin wrote:


> Mike Galbraith wrote:
>
> > At 11:53 AM 8/19/2003 +1000, Nick Piggin wrote:
> >
> > > Hi everyone,
> > >
> > > As per the latest trend these days, I've done some tinkering with
> > > the cpu scheduler. I have gone in the opposite direction of most
> > > of the recent stuff and come out with something that can be nearly
> > > as good interactivity wise (for me).
> > >
> > > I haven't run many tests on it - my mind blanked when I tried to
> > > remember the scores of scheduler "exploits" thrown around. So if
> > > anyone would like to suggest some, or better still, run some,
> > > please do so. And be nice, this isn't my type of scheduler :P
> >
> >
> > Ok, I took it out for a quick spin...
>
>
> Thanks again.
>
> > Test-starve.c starvation is back (curable via other means), but irman2 is 
> > utterly harmless.  Responsiveness under load is very nice until I get to 
> > the "very hefty" end of the spectrum (expected).  Throughput is down a 
> > bit at make -j30, and there are many cc1's running at very high priority 
> > once swap becomes moderately busy.  OTOH, concurrency for the make -jN in 
> > general appears to be up a bit.  X is pretty choppy when moving windows 
> > around, but that _appears_ to be the newer/tamer backboost bleeding a 
> > kdeinit thread a bit too dry.  (I think it'll be easy to correct, will 
> > let you know if what I have in mind to test that theory works 
> > out).  Ending on a decidedly positive note, I can no longer reproduce 
> > priority inversion troubles with xmms's gl thread, nor with blender.
>
>
> Well, it sounds like a good start, though I'll have to get up to scratch
> on the array of scheduler badness programs!

(looks like a fine start to me.  my box [and subjective driver] give it a 
one thumb up plus change;)

> I expect throughput to be down in this release due to the timeslice thing.
> This should be fixable.
>
> I think either there is a bug in my accounting somewhere or I have not quite
> thought it though properly because priorities don't seem to get distributed
> well. Also its not using the nanosecond timing stuff (yet). This might help
> a bit.

Hmm.  I watched priority distribution (eyeballs, not instrumentation), and 
it looked "right" to me until the load reached "fairly hefty"... at the 
point where swap really became a factor, distribution flattened, and the 
mean priority rose (high).  I did see some odd-ball high priority cc1's at 
the low to moderate end (historically indicator of trouble here), but not 
much.  At what I call moderate load, it behaved well, and looked/felt good.

        -Mike 

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