Messages in this thread | | | Date | Sat, 06 Sep 2003 19:40:14 -0700 | From | "Martin J. Bligh" <> | Subject | RE: [PATCH] Minor scheduler fix to get rid of skipping in xmms |
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>> The rationale behind Ingo's patch is to "break up" the timeslices to give > better scheduling latency to >> multiple tasks at the same priority. >> So it is not "unnecessary context switches," just "extra context switches." > > Hmm...my reasoning is that those switches are unnecessary because the > interactivity bonus/penalty will take care of breaking the timeslices up in > case of a CPU hog, albeit not at precise 25 ms granularity. Though having > regularity in scheduling is nice, I think Ingo's patch somewhat negates the > purpose of having heterogenous time slice lengths. I suspect Ingo's > approach will thrash the caches quite a bit more than mine; we should > definitely test this a bit to find out for sure. Any suggestions on how to > go about that? > > If we're going to do a context switch every 25 ms no matter what, we might > as well just make the scheduler a true real time scheduler, dump having > different time slice lengths and interactivity recalculations, and go > completely round robin with strictly enforced priorities and a single class > of time slice somewhere 1 to 5 ms long.
IIRC, that context switching was what sucked on cpu bound jobs (like doing a kernel compile). If you can send me both patches (offline), I'll do a straight comparison on the benchmarking rig I have set up on Monday.
M.
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