| Message ID | 20230913153355.138331-3-james.clark@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf: strcmp_cpuid_str() expression fixups | expand |
On 13/09/2023 16:33, James Clark wrote: > Currently the while loop always either exits on the first iteration with > a core PMU, or exits with NULL on heterogeneous systems or when not all > CPUs are online. > > Both of the latter behaviors are undesirable for platforms other than > Arm so simplify it to always return the first core PMU, or NULL if none > exist. > > This behavior was depended on by the Arm version of > pmu_metrics_table__find(), so the logic has been moved there instead. > > Suggested-by: Ian Rogers <irogers@google.com> > Reviewed-by: Ian Rogers <irogers@google.com> > Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: John Garry <john.g.garry@oracle.com>
On 13/09/2023 16:33, James Clark wrote: > Currently the while loop always either exits on the first iteration with > a core PMU, or exits with NULL on heterogeneous systems or when not all > CPUs are online. > > Both of the latter behaviors are undesirable for platforms other than > Arm so simplify it to always return the first core PMU, or NULL if none > exist. > > This behavior was depended on by the Arm version of > pmu_metrics_table__find(), so the logic has been moved there instead. > > Suggested-by: Ian Rogers <irogers@google.com> > Reviewed-by: Ian Rogers <irogers@google.com> > Signed-off-by: James Clark <james.clark@arm.com> Turns out the "Simple expression parser" test is failing on heterogeneous arm systems without this patch. I didn't realise there was a dependency and should have put the commits the other way round. I will leave the error message here in case someone bumps into it, but no fix is required apart from applying the remaining patches in this set: $ perf test expr -v 4: Simple expression parser : --- start --- test child forked, pid 4902 Using CPUID 0x00000000410fd070 FAILED tests/expr.c:83 get_cpuid test child finished with -1 ---- end ---- Simple expression parser: FAILED! > --- > tools/perf/arch/arm64/util/pmu.c | 8 +++++++- > tools/perf/util/pmus.c | 14 +------------- > 2 files changed, 8 insertions(+), 14 deletions(-) > > diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/pmu.c > index 3d9330feebd2..3099f5f448ba 100644 > --- a/tools/perf/arch/arm64/util/pmu.c > +++ b/tools/perf/arch/arm64/util/pmu.c > @@ -10,8 +10,14 @@ > > const struct pmu_metrics_table *pmu_metrics_table__find(void) > { > - struct perf_pmu *pmu = perf_pmus__find_core_pmu(); > + struct perf_pmu *pmu; > + > + /* Metrics aren't currently supported on heterogeneous Arm systems */ > + if (perf_pmus__num_core_pmus() > 1) > + return NULL; > > + /* Doesn't matter which one here because they'll all be the same */ > + pmu = perf_pmus__find_core_pmu(); > if (pmu) > return perf_pmu__find_metrics_table(pmu); > > diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c > index cec869cbe163..64e798e68a2d 100644 > --- a/tools/perf/util/pmus.c > +++ b/tools/perf/util/pmus.c > @@ -596,17 +596,5 @@ struct perf_pmu *evsel__find_pmu(const struct evsel *evsel) > > struct perf_pmu *perf_pmus__find_core_pmu(void) > { > - struct perf_pmu *pmu = NULL; > - > - while ((pmu = perf_pmus__scan_core(pmu))) { > - /* > - * The cpumap should cover all CPUs. Otherwise, some CPUs may > - * not support some events or have different event IDs. > - */ > - if (RC_CHK_ACCESS(pmu->cpus)->nr != cpu__max_cpu().cpu) > - return NULL; > - > - return pmu; > - } > - return NULL; > + return perf_pmus__scan_core(NULL); > }
diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/pmu.c index 3d9330feebd2..3099f5f448ba 100644 --- a/tools/perf/arch/arm64/util/pmu.c +++ b/tools/perf/arch/arm64/util/pmu.c @@ -10,8 +10,14 @@ const struct pmu_metrics_table *pmu_metrics_table__find(void) { - struct perf_pmu *pmu = perf_pmus__find_core_pmu(); + struct perf_pmu *pmu; + + /* Metrics aren't currently supported on heterogeneous Arm systems */ + if (perf_pmus__num_core_pmus() > 1) + return NULL; + /* Doesn't matter which one here because they'll all be the same */ + pmu = perf_pmus__find_core_pmu(); if (pmu) return perf_pmu__find_metrics_table(pmu); diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index cec869cbe163..64e798e68a2d 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -596,17 +596,5 @@ struct perf_pmu *evsel__find_pmu(const struct evsel *evsel) struct perf_pmu *perf_pmus__find_core_pmu(void) { - struct perf_pmu *pmu = NULL; - - while ((pmu = perf_pmus__scan_core(pmu))) { - /* - * The cpumap should cover all CPUs. Otherwise, some CPUs may - * not support some events or have different event IDs. - */ - if (RC_CHK_ACCESS(pmu->cpus)->nr != cpu__max_cpu().cpu) - return NULL; - - return pmu; - } - return NULL; + return perf_pmus__scan_core(NULL); }