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Re: [PATCH v4] Make bindresvport() function to multithread-safe


On Fri, 2012-09-28 at 13:01 -0400, Carlos O'Donell wrote:
> Peng,
> 
> There are really three things every high quality patch needs:
> 
> (a) Rationale for the change.
> 
> (b) Performance analysis e.g. How does the patch effect the
> performance of the function?

Peng, I've seen that you've been using perf already to get the
performance numbers.  What about comparing cache-misses too?  Perhaps
that could explain why you're seeing improvements when you make things
thread-safe by separating state for different threads.

Also, if possible, I think it's often better to make a hypothesis why
performance would change this or that way due to a patch, and then try
to validate this hypothesis with measurements.  If you just look at
coarse numbers for a certain test case, it might be true that the patch
makes the particular test case on your particular test machine faster,
but then you don't know why; it could be the case that this is just an
outlier, and the patch isn't improving performance in general.

Torvald


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