Re: SMP performance degradation with sysbench

From: Anton Blanchard
Date: Mon Mar 12 2007 - 18:01:12 EST



Hi Nick,

> Anyway, I'll keep experimenting. If anyone from MySQL wants to help look
> at this, send me a mail (eg. especially with the sched_setscheduler issue,
> you might be able to do something better).

I took a look at this today and figured Id document it:

http://ozlabs.org/~anton/linux/sysbench/

Bottom line: it looks like issues in the glibc malloc library, replacing
it with the google malloc library fixes the negative scaling:

# apt-get install libgoogle-perftools0
# LD_PRELOAD=/usr/lib/libtcmalloc.so /usr/sbin/mysqld

Anton
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