Messages in this thread | | | Date | Tue, 11 Mar 2008 22:34:08 +0100 | From | Cyrus Massoumi <> | Subject | Re: Poor PostgreSQL scaling on Linux 2.6.25-rc5 (vs 2.6.22) |
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Nicholas Miell wrote: > On Tue, 2008-03-11 at 17:49 +1100, Nick Piggin wrote: > >> So PostgreSQL performance profile is actually much more interesting. >> To my dismay, I found that Linux 2.6.25-rc5 performs really badly >> after saturating the runqueues and subsequently increasing threads. >> 2.6.22 drops a little bit, but basically settles near the peak >> performance. With 2.6.25-rc5, throughput seems to be falling off >> linearly with the number of threads. >> > > The FreeBSD folks have a whole host of benchmark results (MySQL, > PostgreSQL, BIND, NSD, ebizzy, SPECjbb, etc.) located at > http://people.freebsd.org/~kris/scaling/ that demonstrate that the > 2.6.23+ scheduler is worse than the 2.6.22 scheduler and both are worse > than FreeBSD 7. > > The interesting thing is that they've been running these tests > constantly for years now to demonstrate that their new scheduler hasn't > regressed compared to their old scheduler and as a benchmark against the > competition (i.e. Linux). > > Does anybody even do this at all for Linux? > > (Also, ignoring MySQL because it's a terrible piece of software at least > when regarding it's scalability is a bad idea. It's the M in LAMP, it > has a huge user base, and FreeBSD manages to outperform Linux with the > same unscalable piece of software.)
Did you actually see this? http://www.kernel.org/pub/linux/kernel/people/npiggin/sysbench/
FreeBSD does not outperform Linux, it's actually a bit faster according to Nick's tests.
I cannot comment on BIND and NSD, but SPECjbb looks pretty close and the bad ebizzy performance seems to be an issue with glibc's memory allocator.
greetings Cyrus
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