Messages in this thread | | | Date | Tue, 13 Mar 2007 16:11:02 +1100 | From | Nick Piggin <> | Subject | Re: SMP performance degradation with sysbench |
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Anton Blanchard wrote: > > 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
Hi Anton,
Very cool. Yeah I had come to the conclusion that it wasn't a kernel issue, and basically was afraid to look into userspace ;)
That bogus setscheduler thing must surely have never worked, though. I wonder if FreeBSD avoids the scalability issue because it is using SCHED_RR there, or because it has a decent threaded malloc implementation.
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