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

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:
> http://people.freebsd.org/~davidxu/mysql/mysql_ktrace.txt
> 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:
> http://people.freebsd.org/~davidxu/mysql/iosize.txt

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.

Greg
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