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

From: Ingo Molnar
Date: Thu Mar 27 2008 - 06:45:25 EST



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

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 :-)

Ingo
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