new benchmarks. WAS: FreeBSD MySQL still WAY slower than Linux

Greg 'groggy' Lehey grog at
Mon Dec 12 21:49:16 PST 2005

On Friday,  9 December 2005 at  8:23:26 +0800, David Xu wrote:
> Greg 'groggy' Lehey wrote:
>> I've heard this claim again and again, and I intend to look at it when
>> I have time.  I find it difficult to believe that this alone could
>> explain the sometimes horrendous performance differences (3 to 1) that
>> have been reported.
>> Can somebody tell me:
>> 1.  How many calls there are per second?
>> 2.  Where they're coming from?  This would involve profiling, of
>>   course.
> You find ktrace result of mysql:
> gettimeofday() almost follows every network I/O.

ktrace doesn't give a call graph.  We don't know which function is
calling it.  That's why we need profiling.

> Also you can find its I/O size:

Ugh.  It would be nice to know what those fds are.

> I guess the gettimeofday() call is relevant to mysql's connection
> keepalive work, sounds like a very silly method.

As you say, that's a guess.  We need to find out facts.

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