From: Kevin Wolf <kwolf@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
ming.lei@canonical.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] test-coroutine: add baseline test that times the cost of function calls
Date: Thu, 7 Aug 2014 16:08:53 +0200 [thread overview]
Message-ID: <20140807140853.GD3374@noname.redhat.com> (raw)
In-Reply-To: <20140807093320.GB32038@stefanha-thinkpad.redhat.com>
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Am 07.08.2014 um 11:33 hat Stefan Hajnoczi geschrieben:
> On Wed, Aug 06, 2014 at 11:33:41AM +0200, Paolo Bonzini wrote:
> > This can be used to compute the cost of coroutine operations. In the
> > end the cost of the function call is a few clock cycles, so it's pretty
> > cheap for now, but it may become more relevant as the coroutine code
> > is optimized.
> >
> > For example, here are the results on my machine:
> >
> > Function call 100000000 iterations: 0.173884 s
> > Yield 100000000 iterations: 8.445064 s
> > Lifecycle 1000000 iterations: 0.098445 s
> > Nesting 10000 iterations of 1000 depth each: 7.406431 s
> >
> > One yield takes 83 nanoseconds, one enter takes 97 nanoseconds,
> > one coroutine allocation takes (roughly, since some of the allocations
> > in the nesting test do hit the pool) 739 nanoseconds:
> >
> > (8.445064 - 0.173884) * 10^9 / 100000000 = 82.7
> > (0.098445 * 100 - 0.173884) * 10^9 / 100000000 = 96.7
> > (7.406431 * 10 - 0.173884) * 10^9 / 100000000 = 738.9
> >
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> > tests/test-coroutine.c | 24 ++++++++++++++++
> > 1 files changed, 24 insertions(+)
>
> Can't hurt to have this as a comparison.
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Thanks, applied to the block branch.
Kevin
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next prev parent reply other threads:[~2014-08-07 14:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-06 9:33 [Qemu-devel] [PATCH] test-coroutine: add baseline test that times the cost of function calls Paolo Bonzini
2014-08-07 9:33 ` Stefan Hajnoczi
2014-08-07 14:08 ` Kevin Wolf [this message]
2014-08-11 0:44 ` Ming Lei
2014-08-11 10:08 ` Ming Lei
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