How to view system services use ?
Mikus Grinbergs
mikus at bga.com
Thu Apr 12 16:00:05 UTC 2007
>> 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".
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