Hi Folks,

I have a question regarding how accurate `ps -o cputime` is at reporting
process CPU time from the perspective of how the kernel tabulates such
statistics.

This is on an HP DL-380, 4 x Xeon@3.2GhZ, 4096 Mbytes main memory,
SLES9, service pack 2, stock SLES9 kernel 2.6.8 (if memory serves).

Specifically, I have multiple Java virtual machines (Sun Java JRE-1.5.0)
running on a system (in the form of a Java browser plugin) and I wish to
calculate total CPU time for all running JVMs.
I have a Perl script that calls `ps -o cputime,...` in a loop that iter-
ates for as many times as there are JVMs running. Each time through the
loop, I get the CPU time for the JVM process that the loop is currently
looking at and add it to a running total.

What I want to do is clarify that I can get accurate results via this
method - that `ps` output is accurate and representative of total JVM
CPU time expenditure. Is this the case?

I would also want to do the above CPU time calculation with ps for
Firefox-1.5 and Mozilla-1.7.8 running on the same system.

Any feedback would be appreciated.

Thanks,

Josh.