On Fri, Jan 4, 2013 at 1:23 PM, nobody nowhere <devnull(at)mail(dot)ua> wrote:
>
> ...have you checked which PID is using that core? Is it postgres-related?
>
> How do I know it?
An unfiltered top or ps might give you a clue. You could also try
iotop, php does hit the filesystem (sessions stored in disk), and if
it's on the same partition as postgres, postgres' fsyncs might cause
it to flush to disk quite heavily.