Date: Thu, 22 Nov 2007 18:24:05 +0300 From: Andrew Pantyukhin <infofarmer@freebsd.org> To: Vince <jhary@unsane.co.uk> Cc: questions@freebsd.org Subject: Re: lightly loaded php+mysql - high syscall/csw rates Message-ID: <20071122152404.GE66812@amilo.cenkes.org> In-Reply-To: <47459796.8090006@unsane.co.uk> References: <20071122094324.GD66812@amilo.cenkes.org> <47459796.8090006@unsane.co.uk>
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On Thu, Nov 22, 2007 at 02:52:06PM +0000, Vince wrote: > Andrew Pantyukhin wrote: > > We have a php+mysql web server. It serves 15-20 http requests per > > second, resulting in 100-200 sql qps. But according to vmstat(1), > > it all peaks at over 500k syscall/s and 100k cswitch/s. The peaks > > are quite frequent, even at this load. During the peaks top(1) > > shows 30-40k VCSW for mysql and around 1k vcsw for two php-cgi > > worker processes. IVCSW is relatively very low for all processes. > > > > This is a 4-core Opteron HP DL145 G2 server running 6.2/amd64 > > generic+quota. I'm considering a switch to 7.0. > > > > During peaks user/system/idle in top(1) is 20/30/50. > > > > The question is - is the syscall and csw rates normal or should I > > be trying to tune mysql and php more agressively? I'm not hungry > > for performance (haven't hit the limit yet), but a couple of days > > ago the server stopped responding until a cold reboot (which is > > another story) - and now I'm paying closer attention to its > > vitals. > This sounds like it could be related to the issues being discussed on a > thread on freebsd-stable titled "2 x quad-core system is slower that 2 x > dual core on FreeBSD" > [http://docs.freebsd.org/cgi/mailindex.cgi?sort=subject&file=current/freebsd-stable] Yeah, I'm following that thread, I just wanted to know if anyone else gets 500k+ syscalls per second on an php+mysql web server at 20 pages per second.
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