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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

30
tools/perf/util/pmus.c
View File

@ -87,7 +87,7 @@ static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name)
}
/* Add all pmus in sysfs to pmu list: */
static void pmu_read_sysfs(void)
static void pmu_read_sysfs(bool core_only)
{
int fd;
DIR *dir;
@ -104,6 +104,8 @@ static void pmu_read_sysfs(void)
while ((dent = readdir(dir))) {
if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
continue;
if (core_only && !is_pmu_core(dent->d_name))
continue;
/* add to static LIST_HEAD(core_pmus) or LIST_HEAD(other_pmus): */
perf_pmu__find2(fd, dent->d_name);
}
@ -135,7 +137,7 @@ struct perf_pmu *perf_pmus__scan(struct perf_pmu *pmu)
bool use_core_pmus = !pmu || pmu->is_core;
if (!pmu) {
pmu_read_sysfs();
pmu_read_sysfs(/*core_only=*/false);
pmu = list_prepare_entry(pmu, &core_pmus, list);
}
if (use_core_pmus) {
@ -150,6 +152,18 @@ struct perf_pmu *perf_pmus__scan(struct perf_pmu *pmu)
return NULL;
}
struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *pmu)
{
if (!pmu) {
pmu_read_sysfs(/*core_only=*/true);
pmu = list_prepare_entry(pmu, &core_pmus, list);
}
list_for_each_entry_continue(pmu, &core_pmus, list)
return pmu;
return NULL;
}
const struct perf_pmu *perf_pmus__pmu_for_pmu_filter(const char *str)
{
struct perf_pmu *pmu = NULL;
@ -176,10 +190,10 @@ int perf_pmus__num_mem_pmus(void)
struct perf_pmu *pmu = NULL;
int count = 0;
while ((pmu = perf_pmus__scan(pmu)) != NULL) {
if (perf_pmu__is_mem_pmu(pmu))
count++;
}
/* All core PMUs are for mem events. */
while ((pmu = perf_pmus__scan_core(pmu)) != NULL)
count++;
return count;
}
@ -421,8 +435,8 @@ bool perf_pmus__has_hybrid(void)
if (!hybrid_scanned) {
struct perf_pmu *pmu = NULL;
while ((pmu = perf_pmus__scan(pmu)) != NULL) {
if (pmu->is_core && is_pmu_hybrid(pmu->name)) {
while ((pmu = perf_pmus__scan_core(pmu)) != NULL) {
if (is_pmu_hybrid(pmu->name)) {
has_hybrid = true;
break;
}