Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
perf pmu: Lazily load sysfs aliases
Don't load sysfs aliases for a PMU when the PMU is first created, defer
until an alias needs to be found. For the pmu-scan benchmark, average
core PMU scanning is reduced by 30.8%, and average PMU scanning by
12.6%.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
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: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
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>
Link: https://lore.kernel.org/r/20230824041330.266337-17-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
authored by
Ian Rogers
and committed by
Arnaldo Carvalho de Melo
8d4b6d37
7b723dbb
+46
-39
+2
tools/perf/tests/pmu-events.c
+2
tools/perf/tests/pmu-events.c
···
547
547
pmu->events_table = table;
548
548
pmu_add_cpu_aliases_table(pmu, table);
549
549
pmu->cpu_aliases_added = true;
550
+
pmu->sysfs_aliases_loaded = true;
550
551
551
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res = pmu_events_table__find_event(table, pmu, "bp_l1_btb_correct", NULL, NULL);
552
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if (res != 0) {
···
589
588
pmu->events_table = events_table;
590
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pmu_add_cpu_aliases_table(pmu, events_table);
591
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pmu->cpu_aliases_added = true;
591
+
pmu->sysfs_aliases_loaded = true;
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pmu_add_sys_aliases(pmu);
593
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/* Count how many aliases we generated */
+42
-39
tools/perf/util/pmu.c
+42
-39
tools/perf/util/pmu.c
···
115
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bool loaded;
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};
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+
static int pmu_aliases_parse(struct perf_pmu *pmu);
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+
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static struct perf_pmu_format *perf_pmu__new_format(struct list_head *list, char *name)
119
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{
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struct perf_pmu_format *format;
···
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}
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}
424
422
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-
static struct perf_pmu_alias *perf_pmu__find_alias(const struct perf_pmu *pmu, const char *name)
423
+
static struct perf_pmu_alias *perf_pmu__find_alias(struct perf_pmu *pmu,
424
+
const char *name,
425
+
bool load)
426
426
{
427
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struct perf_pmu_alias *alias;
428
+
429
+
if (load && !pmu->sysfs_aliases_loaded)
430
+
pmu_aliases_parse(pmu);
428
431
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list_for_each_entry(alias, &pmu->aliases, list) {
430
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if (!strcasecmp(alias->name, name))
···
512
505
const char *long_desc = NULL, *topic = NULL, *unit = NULL, *pmu_name = NULL;
513
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bool deprecated = false, perpkg = false;
514
507
515
-
if (perf_pmu__find_alias(pmu, name)) {
508
+
if (perf_pmu__find_alias(pmu, name, /*load=*/ false)) {
516
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/* Alias was already created/loaded. */
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return 0;
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}
···
618
611
}
619
612
620
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/*
621
-
* Process all the sysfs attributes located under the directory
622
-
* specified in 'dir' parameter.
614
+
* Reading the pmu event aliases definition, which should be located at:
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+
* /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
623
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*/
624
-
static int pmu_aliases_parse(struct perf_pmu *pmu, int dirfd)
617
+
static int pmu_aliases_parse(struct perf_pmu *pmu)
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{
619
+
char path[PATH_MAX];
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struct dirent *evt_ent;
627
621
DIR *event_dir;
628
-
int fd;
622
+
size_t len;
623
+
int fd, dir_fd;
629
624
630
-
event_dir = fdopendir(dirfd);
631
-
if (!event_dir)
625
+
len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
626
+
if (!len)
627
+
return 0;
628
+
scnprintf(path + len, sizeof(path) - len, "%s/events", pmu->name);
629
+
630
+
dir_fd = open(path, O_DIRECTORY);
631
+
if (dir_fd == -1) {
632
+
pmu->sysfs_aliases_loaded = true;
633
+
return 0;
634
+
}
635
+
636
+
event_dir = fdopendir(dir_fd);
637
+
if (!event_dir){
638
+
close (dir_fd);
632
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return -EINVAL;
640
+
}
633
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634
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while ((evt_ent = readdir(event_dir))) {
635
643
char *name = evt_ent->d_name;
···
659
637
if (pmu_alias_info_file(name))
660
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continue;
661
639
662
-
fd = openat(dirfd, name, O_RDONLY);
640
+
fd = openat(dir_fd, name, O_RDONLY);
663
641
if (fd == -1) {
664
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pr_debug("Cannot open %s\n", name);
665
643
continue;
···
677
655
}
678
656
679
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closedir(event_dir);
680
-
return 0;
681
-
}
682
-
683
-
/*
684
-
* Reading the pmu event aliases definition, which should be located at:
685
-
* /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
686
-
*/
687
-
static int pmu_aliases(struct perf_pmu *pmu, int dirfd, const char *name)
688
-
{
689
-
int fd;
690
-
691
-
fd = perf_pmu__pathname_fd(dirfd, name, "events", O_DIRECTORY);
692
-
if (fd < 0)
693
-
return 0;
694
-
695
-
/* it'll close the fd */
696
-
if (pmu_aliases_parse(pmu, fd))
697
-
return -1;
698
-
658
+
close (dir_fd);
659
+
pmu->sysfs_aliases_loaded = true;
699
660
return 0;
700
661
}
701
662
···
1019
1014
* now.
1020
1015
*/
1021
1016
if (pmu_format(pmu, dirfd, name)) {
1022
-
free(pmu);
1023
-
return NULL;
1024
-
}
1025
-
/*
1026
-
* Check the aliases first to avoid unnecessary work.
1027
-
*/
1028
-
if (pmu_aliases(pmu, dirfd, name)) {
1029
1017
free(pmu);
1030
1018
return NULL;
1031
1019
}
···
1436
1438
return NULL;
1437
1439
}
1438
1440
1439
-
alias = perf_pmu__find_alias(pmu, name);
1441
+
alias = perf_pmu__find_alias(pmu, name, /*load=*/ true);
1440
1442
if (alias || pmu->cpu_aliases_added)
1441
1443
return alias;
1442
1444
···
1445
1447
pmu_events_table__find_event(pmu->events_table, pmu, name,
1446
1448
pmu_add_cpu_aliases_map_callback,
1447
1449
pmu) == 0) {
1448
-
alias = perf_pmu__find_alias(pmu, name);
1450
+
alias = perf_pmu__find_alias(pmu, name, /*load=*/ false);
1449
1451
}
1450
1452
return alias;
1451
1453
}
···
1618
1620
1619
1621
bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)
1620
1622
{
1621
-
if (perf_pmu__find_alias(pmu, name) != NULL)
1623
+
if (perf_pmu__find_alias(pmu, name, /*load=*/ true) != NULL)
1622
1624
return true;
1623
1625
if (pmu->cpu_aliases_added || !pmu->events_table)
1624
1626
return false;
···
1627
1629
1628
1630
size_t perf_pmu__num_events(struct perf_pmu *pmu)
1629
1631
{
1630
-
size_t nr = pmu->sysfs_aliases;
1632
+
size_t nr;
1633
+
1634
+
if (!pmu->sysfs_aliases_loaded)
1635
+
pmu_aliases_parse(pmu);
1636
+
1637
+
nr = pmu->sysfs_aliases;
1631
1638
1632
1639
if (pmu->cpu_aliases_added)
1633
1640
nr += pmu->loaded_json_aliases;
+2
tools/perf/util/pmu.h
+2
tools/perf/util/pmu.h
···
122
122
uint32_t sysfs_aliases;
123
123
/** @sysfs_aliases: Number of json event aliases loaded. */
124
124
uint32_t loaded_json_aliases;
125
+
/** @sysfs_aliases_loaded: Are sysfs aliases loaded from disk? */
126
+
bool sysfs_aliases_loaded;
125
127
/**
126
128
* @cpu_aliases_added: Have all json events table entries for the PMU
127
129
* been added?