Date: Wed, 14 Mar 2007 12:26:51 -0400 From: Kris Kennaway <kris@obsecurity.org> To: Alban Hertroys <dalroi@solfertje.student.utwente.nl> Cc: Martin <list@manuelmartini.it>, freebsd-stable@freebsd.org, Kris Kennaway <kris@obsecurity.org> Subject: Re: FreeBSD mysql Benchmark on 4BSD/ULE scheduler and i386/amd64 Message-ID: <20070314162650.GA47727@xor.obsecurity.org> In-Reply-To: <41F2E11D-74C4-4901-8050-22B40F7011D4@solfertje.student.utwente.nl> References: <20070313154729.1ec6abb7@DELOREAN.manuelmartini.it> <20070313194206.GA5957@crodrigues.org> <20070313195756.GA11679@xor.obsecurity.org> <20070313211908.59de6504@DELOREAN.manuelmartini.it> <20070313214559.GB13079@xor.obsecurity.org> <330A1347-2309-417E-83B5-5B2CE005B9C8@solfertje.student.utwente.nl> <20070314005546.GA15742@xor.obsecurity.org> <41F2E11D-74C4-4901-8050-22B40F7011D4@solfertje.student.utwente.nl>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 14, 2007 at 09:31:24AM +0100, Alban Hertroys wrote: > On Mar 14, 2007, at 1:55, Kris Kennaway wrote: > > >>This being mysql, the number of processors isn't going to matter > >>much, no matter how many connections you have. Mysql doesn't scale > >>very well to multiple cpu's. > > > >This might be standard dogma, but it also appears not to be true: > > > > http://people.freebsd.org/~kris/scaling/mysql.html > > Interesting. Results I have seen using a 16 CPU SGI Altex(?) showed > an almost linear rise for postgres while mysql topped off after about > 4 threads. Sorry, don't have the URL at hand (I probably still have > it in my work mail). OK, based on the above results you already know it's at least partly incorrect on FreeBSD with our scalability fixes. i.e. it is not a limitation of mysql itself. > Now this may well have been a version before 5.0.33. I'm not sure > what OS was used either, I suppose it was either Irix or Linux. > > Now I am curious whether the same performance drop on Linux would > occur with a postgres benchmark. It probably will, but if not it > seems like there's a problem in the way that mysql and linux interact. The linux scaling problem was traced to glibc malloc, so postgresql may not be affected in the same way since it is not threaded. Kris
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070314162650.GA47727>