eliminate duplicate uncore events across groups as this causes perf to misreport event values #565
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…o misreport event values Signed-off-by: Harper, Jason M <jason.m.harper@intel.com>
Signed-off-by: Harper, Jason M <jason.m.harper@intel.com>
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branched from v3.12.0 to address critical bug fix: #564
The problem addressed is in the way that PerfSpect forms the event groups for collection from Linux perf. When UNC_CHA_CLOCKTICKS, and possibly other uncore events, appear in more than one group, the event count value reported by perf is significantly elevated. This results in the observed issue described in the bug report, i.e., uncore frequency metric is much too high and out of the range of possibility. Other metrics that rely on the same events are similarly impacted.
This PR limits uncore events to appear only one time in all uncore groups.