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Re: [PATCH] Converted benchmark to benchtest.

On Thu, Jun 05, 2014 at 06:07:01PM +0530, Siddhesh Poyarekar wrote:
> On Sat, May 03, 2014 at 12:48:31PM +0200, OndÅej BÃlka wrote:
> > Its nice to have but orthogonal on proposed change, so it should not
> > block this patch
> This looks like something that could easily use the $bench-inputs
> format since you're really just looking for mean times.  I haven't
> checked to see if a failed branch would be expensive compared to the
> lock/unlock cycle we're testing, but I'm guessing that it should get
> cached and hence not have an impact since we don't interleave the
> rdlock and wrlock calls.
I assume that you asked about branch misprediction, that should not be
problem here, there are two ways how that it could happen. First one is
that it was not cache but then this is in cold path so it is not that
interesting. Second possibility is that we took different path previous
time, this is also not that interesting because previous call went to
slow path which was order of magnitude slower so its contribution is

A third case where misprediction can happen is that there are parallel
readers. That would need a different benchmark.

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