Re: [CFT][PATCH] new scheduler policy

Mike Galbraith
2003-08-19T18:50:14Z

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