Date: Tue, 3 Jan 2012 09:05:16 +0100 From: Victor Balada Diaz <victor@bsdes.net> To: Artem Belevich <art@freebsd.org> Cc: freebsd-stable@freebsd.org, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: Performance problems with pagedaemon Message-ID: <20120103080515.GA36252@equilibrium.bsdes.net> In-Reply-To: <CAFqOu6gjn7WoHo8vjupFEj9BsWvjYLkdp5z=9GqEXBVcW8UgEA@mail.gmail.com> References: <20120102122549.GB17398@equilibrium.bsdes.net> <20120102125929.GA89966@icarus.home.lan> <20120102134150.GC17398@equilibrium.bsdes.net> <CAFqOu6gjn7WoHo8vjupFEj9BsWvjYLkdp5z=9GqEXBVcW8UgEA@mail.gmail.com>
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On Mon, Jan 02, 2012 at 10:17:11AM -0800, Artem Belevich wrote: > On Mon, Jan 2, 2012 at 5:41 AM, Victor Balada Diaz <victor@bsdes.net> wrote: > > Mysql uses more than 20G of RAM. You may want to tune it down a bit so > that there is a bit of free RAM around. > > Page daemon is trying to maintain v_free_target + v_cache_min. > > >vm.v_free_target: 161771 > >vm.v_cache_min: 161771 > > In your case that would be about 1.2GB. If 'v_free_count + > v_cache_count' are below that page daemon will periodically wake up > and will start scanning active/inactive lists trying to find the pages > it could use. In your case, when most of the memory is in active use, > page daemon's job will be almost pointless and would just waste CPU > time. > > On large memory systems default tuning for v_free/cache_min/target is > probably somewhat conservative. You may try setting them somewhat > lower via sysctl and see if you can find an equilibrium with mysql > happy, pagedaemon sleeping and the system up and running. The danger > of tuning these parameters too low is that is you don't have enough > memory available for allocation without having to sleep, things will > start falling apart and will eventually hang or crash your box. That was the problem. Thanks a lot! Is there any place or documentation about how to properly tune the VM? None of the sysctls you mentioned have description or appear to be in any man page. -- La prueba más fehaciente de que existe vida inteligente en otros planetas, es que no han intentado contactar con nosotros.
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