Messages in this thread | | | Date | Thu, 19 Jun 2014 16:07:32 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [bisected] pre-3.16 regression on open() scalability |
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On Thu, Jun 19, 2014 at 02:32:03PM -0700, josh@joshtriplett.org wrote: > On Thu, Jun 19, 2014 at 04:16:34PM -0500, Christoph Lameter wrote: > > This looks very much like the CONFIG_PREEMPT problem in not so > > extreme form. Maybe we need to add another config option: > > > > CONFIG_REALLY_REALLY_NO_PREEMPT > > > > to get the fastest code possible and those cond_rescheds removed from the > > critical paths? > > > > Or better > > > > CONFIG_PREEMPT_HALF_WAY > > > > to enable those cond_rescheds. > > That much actually does seem quite reasonable: making cond_resched() do > non-trivial work ought to have a config option to disable it.
I am putting together patches based on Eric Dumazet's suggestion and on a variant of the above approach. However, I do expect the distros to starve to death between those two bales of hay. But perhaps the actual patches will inspire a bit of light to go with this thread's heat and smoke.
Thanx, Paul
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