How to view system services use ?

[Mikus Grinbergs]

 >> My question -- what facilities/tools
 >> are available for me to determine "what services is the system
 >> running at the instant that system mode is taking this noticeable
 >> percentage of the CPU" ?
 >
 > You could run System Monitor and keep and eye on it for a while
 > and see if you can notice what process is taking over. Click on
 > SYSTEM ADMINISTRATION > SYSTEM MONITOR. There are three tabs.
 > One of them will show you the running processes, which can then
 > be ordered according to CPU usage. Other than that I am not too
 > sure. Any other ideas?

The particular case that I am interested in, I have a good idea
which *process* is requesting system services.  (Remember, the 
system usage shows up on 'top'.)  But I do not have the source of
the application, so I do not know which *services* the process is
invoking.  That's what I'm really after -- what is that process
doing that causes so many millions of system-mode instructions to
be executed?  [A previous version of the same application did not
exhibit this (to me excessive) system-mode usage.]

Besides, some of those 'spikes' of system-mode execution show up on
'gkrellm' when __no__ "interesting" process is being shown by 'top'
as running.  So they must represent internal (non-process) Ubuntu
functions.  I would like to know what those are, too.

mikus  (using 64-bit Ubuntu 6.10)


p.s.  Seems to be a bug in 'System Monitor'.  This is a muti-core
       system, but while 'System Monitor' shows the correct percent
       (of the *whole* system's CPU capability) for each of the
       running (long-term) processes, it labels only the one in CPU0
       as "Running".  The (nice-mode) processes running in the other
       CPUs have their status labeled as "Sleeping".