netdev - [PATCH v3 0/5] Make evlist CPUs more accurate

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Date:   Thu,  7 Apr 2022 20:56:11 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Kajol Jain <kjain@...ux.ibm.com>,
        James Clark <james.clark@....com>,
        German Gomez <german.gomez@....com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Riccardo Mancini <rickyman7@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org
Cc:     Stephane Eranian <eranian@...gle.com>,
        Ian Rogers <irogers@...gle.com>
Subject: [PATCH v3 0/5] Make evlist CPUs more accurate

evlist has all_cpus, computed to be the merge of all evsel CPU maps,
and cpus. cpus may contain more CPUs than all_cpus, as by default cpus
holds all online CPUs whilst all_cpus holds the merge/union from
evsels. For an uncore event there may just be 1 CPU per socket, which
will be a far smaller CPU map than all online CPUs.

The v1 patches changed cpus to be called user_requested_cpus, to
reflect their potential user specified nature. The user_requested_cpus
are set to be the current value intersected with all_cpus, so that
user_requested_cpus is always a subset of all_cpus. This fixes
printing code for metrics so that unnecessary blank lines aren't
printed.

To make the intersect function perform well, a perf_cpu_map__is_subset
function is added. While adding this function, the v2 patches also
used it in perf_cpu_map__merge to avoid creating a new CPU map for
some currently missed patterns. The reference counts for these
functions is simplified as discussed here:
https://lore.kernel.org/lkml/YkdOpJDnknrOPq2t@kernel.org/ but this
means users of perf_cpu_map__merge must now do a put on the 1st
argument.

v2. Reorders the "Avoid segv" patch and makes other adjustments
    suggested by Arnaldo Carvalho de Melo <acme@...nel.org>.
v3. Modify reference count behaviour for merge and intersect. Add
    intersect tests and tidy thee cpu map tests suite.

Ian Rogers (5):
  perf cpumap: Don't decrement refcnt on args to merge
  perf tests: Additional cpumap merge tests
  perf cpumap: Add intersect function.
  perf evlist: Respect all_cpus when setting user_requested_cpus
  perf test: Combine cpu map tests into 1 suite

 tools/lib/perf/cpumap.c              | 46 ++++++++++++++---
 tools/lib/perf/evlist.c              |  6 ++-
 tools/lib/perf/include/perf/cpumap.h |  2 +
 tools/perf/tests/builtin-test.c      |  4 +-
 tools/perf/tests/cpumap.c            | 74 +++++++++++++++++++++++++---
 tools/perf/tests/tests.h             |  4 +-
 tools/perf/util/evlist.c             |  7 +++
 7 files changed, 120 insertions(+), 23 deletions(-)

-- 
2.35.1.1178.g4f1659d476-goog