Obtaining l2 misses and cpu utilization in a module

David Wolfskill david at catwhisker.org
Wed Feb 18 13:56:20 PST 2009


On Wed, Feb 18, 2009 at 08:18:20PM +0100, Nikola Kne??evi?? wrote:
> Hi,
> 
> I would like to obtain fore mentioned data from within my module. I  
> need these performance metrics to see how certain code executes, and  
> make decisions during the runtime. pmc(3) seems complete, but it also  
> seems to be intended for use in the userland.
> 
> How to use pmc from modules? Is there any other way? Also, module is  
> amd64 only, so I don't care about portability.

I'm not sure what you mean by "module" ini this context.

But CPU utilization my be found in the kern.cp_time sysctl value;
per-core utilization may be found in the kern.cp_times sysctl value.

Note that these are arrays of counters; a given set of values will be
foir "user", "nice", "system", "interrupt", and "idle" CPU time (in that
order).  The differences between respective counters at each end of a
time interval of interest will be informative.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Depriving a girl or boy of an opportunity for education is evil.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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