Re: [PATCH 0/5] Generic smp_call_function(), improvements, andsmp_call_function_single()

From: Ingo Molnar
Date: Thu Mar 27 2008 - 08:33:13 EST



* Jens Axboe <jens.axboe@xxxxxxxxxx> 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.)

Ingo
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