Messages in this thread |  | | | Subject | Re: [PATCH 0/4] pending scheduler updates | | From | Mike Galbraith <> | | Date | Wed, 22 Oct 2008 19:56:55 +0200 |
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On Wed, 2008-10-22 at 19:38 +0200, Peter Zijlstra wrote: > On Wed, 2008-10-22 at 12:32 +0200, Mike Galbraith wrote: > > On Wed, 2008-10-22 at 12:03 +0200, Mike Galbraith wrote: > > > > > It has positive effects too, but IMHO, the bad outweigh the good. > > > > BTW, most dramatic on the other end of the spectrum is pgsql+oltp. With > > preemption as is, it collapses as load climbs to heavy with preemption > > knobs at stock. Postgres uses user-land spinlocks and _appears_ to wake > > others while these are still held. For this load, there is such a thing > > as too much short-term fairness, preempting lock holder creates nasty > > gaggle of contended lock spinners. It's curable with knobs, and I think > > it's postgres's own fault, but may be wrong. > > > > With that patch, pgsql+oltp scales perfectly. > > Are we talking about this patch, which re-instates the vruntime based > wakeup-preemption ?
No, if it was that one, I'd be tinkering with mysql+oltp. Everything else I tested (limited time, but fairly wide spectrum) with that patch was fine, including interactivity. Caveat: tbench/netperf test results I'm not comfortable with, would need to backport to 26 to feel at all confident with those. (fwtw)
-Mike
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