On Wed, Feb 16, 2011 at 6:44 AM, Marti Raudsepp <ma...@juffo.org> wrote: > On Tue, Feb 15, 2011 at 20:01, Scott Marlowe <scott.marl...@gmail.com> wrote: >> run htop and look for red. if youi've got lots of red bar on each CPU >> but no io wait then it's waiting for memory access. > > I don't think this is true. AFAICT the red bar refers to "system > time", time that's spent in the kernel -- either in syscalls or kernel > background threads.
My point being that if you've got a lot of RED it'll be the OS waiting for memory access. Trust me, when we start to hit our memory bandwidth (in the 70 to 80 GB/s range) we start to get more and more red and more and more kernel wait time. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
