2 x quad-core system is slower that 2 x dual core on FreeBSD

Alexey Popov lol at chistydom.ru
Mon Nov 19 06:24:15 PST 2007


Robert Watson wrote:
>> Also I faced the same problem moving heavily loaded MySQL-server to 
>> new hardware. That time I thought that the problem is in the 
>> mysql-server itself and I had to install Linux.
>> What can I do to make FreeBSD run faster on many-CPU systems???
> Have you configured libmap.conf to force MySQL to use libthr instead of 
> libpthread?  libpthread is known to have serious performance bottlenecks 
> for MySQL as compared to libthr.
I'm always using libthr with MySQL on 6-STABLE and it really helps. But 
that time with MySQL (and this time with Apache) the bottleneck was 
somewhere else.

> FreeBSD 7 contains significant optimization for increased numbers of 
> cores, and is where a lot of the work optimizing MySQL has ended up.  I 
> see you're trying out a 6.3 beta, any chance you could try out a 7.0 
> beta instead? Also, consider switching to "options SCHED_ULE" in the 7.0 
> kernel rather than "options SCHED_4BSD".
I tried 7-BETA with SHED_4BSD and id did not help. Now I'll try 
SHED_ULE, thanks.

With best regards,
Alexey Popov

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