hwpmc overflow

George Neville-Neil gnn at freebsd.org
Tue Sep 27 22:36:08 UTC 2011

On Sep 21, 2011, at 01:48 , Anton Yuzhaninov wrote:

> On Wed, 21 Sep 2011 09:27:33 +0800, Adrian Chadd wrote:
> AC> Is this an AMD class CPU?
> AC> 
> AC> The way the counters work on some platforms is that they count _up_ to
> AC> an overflow value, trigger the overflow interrupt, and PMC then is
> AC> supposed to calculate what the original value was.
> AC> It sounds like maybe that isn't working correctly for a certain class
> AC> of counters?
> CPU: Intel(R) Xeon(R) CPU E5645 @ 2.40GHz

If you count them individually do you still get the overflows?  That is, if you run
the same workload but only count instructions, then run it again with the next counter,
etc.  I am wondering if something is wrong because of the number of things you're trying
to count at the same time.


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