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perf pmus: Allow just core PMU scanning

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Scanning all PMUs is expensive as all PMUs sysfs entries are loaded,
benchmarking shows more than 4x the cost:

```
$ perf bench internals pmu-scan -i 1000
Computing performance of sysfs PMU event scan for 1000 times
  Average core PMU scanning took: 989.231 usec (+- 1.535 usec)
  Average PMU scanning took: 4309.425 usec (+- 74.322 usec)
```

Add new perf_pmus__scan_core routine that scans just core
PMUs. Replace perf_pmus__scan calls with perf_pmus__scan_core when
non-core PMUs are being ignored.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kang Minchul <tegongkang@gmail.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230527072210.2900565-30-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers
2023-05-27 00:22:05 -07:00
committed by Arnaldo Carvalho de Melo
parent 15c57a8037
commit 9d6a1df9b2
14 changed files with 73 additions and 94 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tools/perf/bench/pmu-scan.c
+27 -19
View File
@@ -22,6 +22,7 @@ struct pmu_scan_result {
int nr_aliases;
int nr_formats;
int nr_caps;
bool is_core;
};
static const struct option options[] = {
@@ -53,6 +54,7 @@ static int save_result(void)
r = results + nr_pmus;
r->name = strdup(pmu->name);
r->is_core = pmu->is_core;
r->nr_caps = pmu->nr_caps;
r->nr_aliases = 0;
@@ -72,7 +74,7 @@ static int save_result(void)
return 0;
}
static int check_result(void)
static int check_result(bool core_only)
{
struct pmu_scan_result *r;
struct perf_pmu *pmu;
@@ -81,6 +83,9 @@ static int check_result(void)
for (int i = 0; i < nr_pmus; i++) {
r = &results[i];
if (core_only && !r->is_core)
continue;
pmu = perf_pmus__find(r->name);
if (pmu == NULL) {
pr_err("Cannot find PMU %s\n", r->name);
@@ -130,7 +135,6 @@ static int run_pmu_scan(void)
struct timeval start, end, diff;
double time_average, time_stddev;
u64 runtime_us;
unsigned int i;
int ret;
init_stats(&stats);
@@ -142,26 +146,30 @@ static int run_pmu_scan(void)
return -1;
}
for (i = 0; i < iterations; i++) {
gettimeofday(&start, NULL);
perf_pmus__scan(NULL);
gettimeofday(&end, NULL);
for (int j = 0; j < 2; j++) {
bool core_only = (j == 0);
timersub(&end, &start, &diff);
runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
update_stats(&stats, runtime_us);
for (unsigned int i = 0; i < iterations; i++) {
gettimeofday(&start, NULL);
if (core_only)
perf_pmus__scan_core(NULL);
else
perf_pmus__scan(NULL);
gettimeofday(&end, NULL);
timersub(&end, &start, &diff);
runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
update_stats(&stats, runtime_us);
ret = check_result();
perf_pmus__destroy();
if (ret < 0)
break;
ret = check_result(core_only);
perf_pmus__destroy();
if (ret < 0)
break;
}
time_average = avg_stats(&stats);
time_stddev = stddev_stats(&stats);
pr_info(" Average%s PMU scanning took: %.3f usec (+- %.3f usec)\n",
core_only ? " core" : "", time_average, time_stddev);
}
time_average = avg_stats(&stats);
time_stddev = stddev_stats(&stats);
pr_info(" Average PMU scanning took: %.3f usec (+- %.3f usec)\n",
time_average, time_stddev);
delete_result();
return 0;
}