Metric groups contain metrics. Metrics create groups of events to ideally be scheduled together. Often metrics refer to the same events, for example, a cache hit and cache miss rate. Using separate event groups means these metrics are multiplexed at different times and the counts don't sum to 100%. More multiplexing also decreases the accuracy of the measurement. This change orders metrics from groups or the command line, so that the ones with the most events are set up first. Later metrics see if groups already provide their events, and reuse them if possible. Unnecessary events and groups are eliminated. RFC because: - without this change events within a metric may get scheduled together, after they may appear as part of a larger group and be multiplexed at different times, lowering accuracy - however, less multiplexing may compensate for this. - libbpf's hashmap is used, however, libbpf is an optional requirement for building perf. - other things I'm not thinking of. Thanks! v2. is the entire patch set based on acme's perf/core tree and includes a cherry-picks. Patch 13 was sent for review to the bpf maintainers here: https://lore.kernel.org/lkml/20200506205257.8964-2-irogers@xxxxxxxxxx/ v1. was based on the perf metrics fixes and test sent here: https://lore.kernel.org/lkml/20200501173333.227162-1-irogers@xxxxxxxxxx/ Andrii Nakryiko (1): libbpf: Fix memory leak and possible double-free in hashmap__clear Ian Rogers (22): perf expr: unlimited escaped characters in a symbol perf metrics: fix parse errors in cascade lake metrics perf metrics: fix parse errors in skylake metrics perf expr: allow ',' to be an other token perf expr: increase max other perf expr: parse numbers as doubles perf expr: debug lex if debugging yacc perf metrics: fix parse errors in power8 metrics perf metrics: fix parse errors in power9 metrics perf expr: print a debug message for division by zero perf parse-events: expand add PMU error/verbose messages perf test: improve pmu event metric testing lib/bpf hashmap: increase portability perf expr: fix memory leaks in bison perf evsel: fix 2 memory leaks perf expr: migrate expr ids table to libbpf's hashmap perf metricgroup: change evlist_used to a bitmap perf metricgroup: free metric_events on error perf metricgroup: always place duration_time last perf metricgroup: delay events string creation perf metricgroup: order event groups by size perf metricgroup: remove duped metric group events tools/lib/bpf/hashmap.c | 7 + tools/lib/bpf/hashmap.h | 3 +- tools/perf/arch/x86/util/intel-pt.c | 32 ++- .../arch/powerpc/power8/metrics.json | 2 +- .../arch/powerpc/power9/metrics.json | 2 +- .../arch/x86/cascadelakex/clx-metrics.json | 10 +- .../arch/x86/skylakex/skx-metrics.json | 4 +- tools/perf/tests/builtin-test.c | 5 + tools/perf/tests/expr.c | 33 ++- tools/perf/tests/pmu-events.c | 158 +++++++++++- tools/perf/tests/pmu.c | 4 +- tools/perf/tests/tests.h | 2 + tools/perf/util/evsel.c | 2 + tools/perf/util/expr.c | 126 ++++----- tools/perf/util/expr.h | 22 +- tools/perf/util/expr.l | 16 +- tools/perf/util/expr.y | 41 ++- tools/perf/util/metricgroup.c | 242 +++++++++++------- tools/perf/util/parse-events.c | 29 ++- tools/perf/util/pmu.c | 33 ++- tools/perf/util/pmu.h | 2 +- tools/perf/util/stat-shadow.c | 46 ++-- 22 files changed, 545 insertions(+), 276 deletions(-) -- 2.26.2.526.g744177e7f7-goog
