Messages in this thread | | | Date | Thu, 27 Mar 2008 13:02:44 +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 very much wanted the kthread approach to work, since it's easier to > > work with. It's not for lack of will or trying... I'll be happy to > > supply you otherwise identical patches for this, the only difference > > being kthread of IPI completions if you want to play with this. > > 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.
> Obviously since the kthread approach embedds IPI sending it can never be > as fast as a pure IPI approach - but it should still be reasonably fast. > 3 usecs versus 2 usecs in a microbenchmark sounds about right to me, but > it would be better to make it a better-sounding 2.5 usecs versus 2 usecs > or so :-)
If you have ideas to speedup the kthread approach, fire away :-)
-- Jens Axboe
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