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authorIan Rogers <irogers@google.com>2023-05-19 09:37:18 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2023-06-05 21:56:14 +0300
commit6f765bbbfb3c8c5993796402a3cba311e9506eed (patch)
tree722d29bbf4ebfc6094adab39caddcf870e19056c /tools/perf/Documentation
parent269f49f9cb1e94732ec1738d0b1af4653cadd2f5 (diff)
downloadlinux-6f765bbbfb3c8c5993796402a3cba311e9506eed.tar.xz
perf expr: Make the evaluation of & and | logical and lazy
Currently the & and | operators are only used in metric thresholds like (from the tma_retiring metric): tma_retiring > 0.7 | tma_heavy_operations > 0.1 Thresholds are always computed when present, but a lack of events may mean the threshold can't be computed. This happens with the option --metric-no-threshold for say the metric tma_retiring on Tigerlake model CPUs. To fully compute the threshold tma_heavy_operations is needed and it needs the extra events of IDQ.MS_UOPS, UOPS_DECODED.DEC0, cpu/UOPS_DECODED.DEC0,cmask=1/ and IDQ.MITE_UOPS. So --metric-no-threshold is a useful option to reduce the number of events needed and potentially multiplexing of events. Rather than just fail threshold computations like this, we may know a result from just the left or right-hand side. So, for tma_retiring if its value is "> 0.7" we know it is over the threshold. This allows the metric to have the threshold coloring, when possible, without all the counters being programmed. Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Kan Liang <kan.liang@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ahmad Yasin <ahmad.yasin@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Caleb Biggers <caleb.biggers@intel.com> Cc: Eduard Zingerman <eddyz87@gmail.com> Cc: Edward Baker <edward.baker@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Perry Taylor <perry.taylor@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Samantha Alt <samantha.alt@intel.com> Cc: Stephane Eranian <eranian@google.com> Cc: Weilin Wang <weilin.wang@intel.com> Link: https://lore.kernel.org/r/20230519063719.1029596-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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