Hello Dan,
On Feb 9, 2008 8:52 PM, Dan Upton <upton@...> wrote:
> Hi all,
>
> I recently installed perfmon2 on a Core2 Duo running kernel 2.6.23.14.
> I noticed under /sys/devices/system/cpu/cpuN, there's a perfmon
> directory that seems to have references to various counting
> structures. Is there any documentation for these files? Specifically
There is documentation in the kernel source tree:
Documentation/ABI/testing/sysfs-perfmon-stats
However note that those files report perfmon internal performance/debug
statistics. They are unrelated to the actual performance counters. The
counts are global and not per-process.
> I'm wondering if there's anyway to use these files so that one process
> could read performance data about another--basically, one application
> is pinned to a core and starts the performance counters (either itself
> or via being executed under pfmon), and then a second application
> could just read those files to see live counter values.
>
You do not need to run on CPUX to read stats about CPUx. But no
counter values are reported that way, even for system-wide measurements.
In system-wide, you need to run on the monitored CPUs to read the performance
counters.
Hope this helps.
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