system time on top output

[Omer Faruk Sen]

Hi,

I have a running pgsql server but on heavy loads it consumes lots of
time in system (more than %50). I can see that

CPU states: 15.4% user,  0.0% nice, 81.9% system,  1.5% interrupt,  1.2% idle

But how can I debug that kind of system. vmstat and other tools only
show most cpu is used by system. But how can I go deeper and debug
that kind of a problem?
Any tools that you can suggest me?