From mboxrd@z Thu Jan 1 00:00:00 1970
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Subject: PEBS availability
Date: Tue, 24 May 2011 16:49:27 +0100
Message-ID: <4DDBD387.2070906@draigBrady.com>
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Hi,
I've just got a shiny new i3-2310M and am a
bit surprised that `perf` isn't listing
detailed stats like L1 cache misses etc.
$ perf stat true
Performance counter stats for 'true':
1,239 cache-misses # 1.555 M/sec
9,314 cache-references # 11.693 M/sec
3,940 branch-misses # 4.871 %
80,885 branches # 101.546 M/sec
403,808 instructions # 0.000 IPC
cycles
81 page-faults # 0.102 M/sec
0 CPU-migrations # 0.000 M/sec
1 context-switches # 0.001 M/sec
0.796537 task-clock-msecs # 0.032 CPUs
0.024654938 seconds time elapsed
I searched for a while but found it _very_ difficult
to find info on what was available on particular intel CPUs.
I did see in the "Nehalem Core PMU programming guide":
http://software.intel.com/file/30320
that the above stats are core features and that the other
counters I mentioned are PEBS (Precise Event Based Sampling)
and are not available on all systems.
So am I out of look with my new i3 sandy bridge CPU?
Are PEBS restricted to i7 versions only?
Is this documented anywhere?
Maybe I need some kernel support as hinted at by:
http://lwn.net/Articles/430100/
My kernel is 2.6.38.6-27.fc15.x86_64
cheers.
P=C3=A1draig.