perf stat: Save aggr value to first member of prev_raw_counts
To collect the overall statistics for interval mode, we copy the counts from evsel->prev_raw_counts to evsel->counts. For AGGR_GLOBAL mode, because the perf_stat_process_counter creates aggr values from per cpu values, but the per cpu values are 0, so the calculated aggr values will be always 0. This patch uses a trick that saves the previous aggr value to the first member of perf_counts, then aggr calculation in process_counter_values can work correctly for AGGR_GLOBAL. v6: --- Add comments in perf_evlist__save_aggr_prev_raw_counts. Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@intel.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20200520042737.24160-5-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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