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Sukadev Bhattiprolu authored
For 24x7 counters, perf displays the raw value of the 24x7 counter, which is a monotonically increasing value. perf stat -C 0 -e \ 'hv_24x7/HPM_0THRD_NON_IDLE_CCYC__PHYS_CORE,core=1/' \ sleep 1 Performance counter stats for 'CPU(s) 0': 9,105,403,170 hv_24x7/HPM_0THRD_NON_IDLE_CCYC__PHYS_CORE,core=1/ 0.000425751 seconds time elapsed In the typical usage of 'perf stat' this counter value is not as useful as the _change_ in the counter value over the duration of the application. Have h_24x7_event_init() set the event's prev_count to the raw value of the 24x7 counter at the time of initialization. When the application terminates, hv_24x7_event_read() will compute the change in value and report to the perf tool. Similarly, for the transaction interface, clear the event count to 0 at the beginning of the transaction. perf stat -C 0 -e \ 'hv_24x7/HPM_0THRD_NON_IDLE_CCYC__PHYS_CORE,core=1/' \ sleep 1 Performance counter stats for 'CPU(s) 0': 245,758 hv_24x7/HPM_0THRD_NON_IDLE_CCYC__PHYS_CORE,core=1/ 1.006366383 seconds time elapsed Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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