Messages in this thread | | | Date | Thu, 27 Mar 2008 13:35:25 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH 0/5] Generic smp_call_function(), improvements, and smp_call_function_single() |
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On Thu, Mar 27 2008, Ingo Molnar wrote: > > * Jens Axboe <jens.axboe@oracle.com> wrote: > > > > i'd love to be able to run/pull something simple that enables me to > > > replicate the measurements you did on a generic PC [without having > > > to hit any real IO hardware which would put any context switching > > > effects down into the noise category]. > > > > You can pull io-cpu-affinity or io-cpu-affinity-kthread from > > git://git.kernel.dk/linux-2.6-block.git - or just see the two attached > > patches, apply either one to current -git to test it. > > another stupid question: what should i run in user-space to replicate > your "3 usecs versus 2 usecs" result? io-affinity-ipi.patch seems to > have no self-benchmarking capability at first sight. (I'd rather not try > and cook up anything myself - i'd like to reproduce the workload you > think is relevant for your IO affinity purposes.) Best would be to have > a Kconfig based self-test that just runs during bootup if i boot a > bzImage. (laziness rules - and this way i could also track performance > regressions more easily, by looking at historic serial logs.)
I didn't do those numbers - Alan, when you timed the kthread vs ipi "wake up", what did you use? I'm guessing some hacked in test, perhaps you can pass that to Ingo?
-- Jens Axboe
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