From 7b723dbb96e85a63a8f01e2b3fdfb76aa5d418a8 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Wed, 23 Aug 2023 21:13:27 -0700 Subject: [PATCH] perf pmu: Be lazy about loading event info files from sysfs Event info is only needed when an event is parsed or when merging data from an JSON and sysfs event. Be lazy in its loading to reduce file accesses. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Gaosheng Cui Cc: Ingo Molnar Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Rob Herring Link: https://lore.kernel.org/r/20230824041330.266337-16-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/pmu.c | 128 +++++++++++++++++++++++++++--------------- 1 file changed, 83 insertions(+), 45 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 9e3b72d84168..493d3e59fd50 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -58,6 +58,11 @@ struct perf_pmu_alias { struct list_head terms; /** @list: List element of struct perf_pmu aliases. */ struct list_head list; + /** + * @pmu_name: The name copied from the json struct pmu_event. This can + * differ from the PMU name as it won't have suffixes. + */ + char *pmu_name; /** @unit: Units for the event, such as bytes or cache lines. */ char unit[UNIT_MAX_LEN+1]; /** @scale: Value to scale read counter values by. */ @@ -79,11 +84,10 @@ struct perf_pmu_alias { * default. */ bool deprecated; - /** - * @pmu_name: The name copied from the json struct pmu_event. This can - * differ from the PMU name as it won't have suffixes. - */ - char *pmu_name; + /** @from_sysfs: Was the alias from sysfs or a json event? */ + bool from_sysfs; + /** @info_loaded: Have the scale, unit and other values been read from disk? */ + bool info_loaded; }; /** @@ -280,17 +284,21 @@ out: return ret; } -static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, int dirfd, const char *name) +static int perf_pmu__parse_scale(struct perf_pmu *pmu, struct perf_pmu_alias *alias) { struct stat st; ssize_t sret; + size_t len; char scale[128]; int fd, ret = -1; char path[PATH_MAX]; - scnprintf(path, PATH_MAX, "%s.scale", name); + len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path)); + if (!len) + return 0; + scnprintf(path + len, sizeof(path) - len, "%s/%s.scale", pmu->name, alias->name); - fd = openat(dirfd, path, O_RDONLY); + fd = open(path, O_RDONLY); if (fd == -1) return -1; @@ -312,15 +320,20 @@ error: return ret; } -static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, int dirfd, const char *name) +static int perf_pmu__parse_unit(struct perf_pmu *pmu, struct perf_pmu_alias *alias) { char path[PATH_MAX]; + size_t len; ssize_t sret; int fd; - scnprintf(path, PATH_MAX, "%s.unit", name); - fd = openat(dirfd, path, O_RDONLY); + len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path)); + if (!len) + return 0; + scnprintf(path + len, sizeof(path) - len, "%s/%s.unit", pmu->name, alias->name); + + fd = open(path, O_RDONLY); if (fd == -1) return -1; @@ -343,14 +356,18 @@ error: } static int -perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, int dirfd, const char *name) +perf_pmu__parse_per_pkg(struct perf_pmu *pmu, struct perf_pmu_alias *alias) { char path[PATH_MAX]; + size_t len; int fd; - scnprintf(path, PATH_MAX, "%s.per-pkg", name); + len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path)); + if (!len) + return 0; + scnprintf(path + len, sizeof(path) - len, "%s/%s.per-pkg", pmu->name, alias->name); - fd = openat(dirfd, path, O_RDONLY); + fd = open(path, O_RDONLY); if (fd == -1) return -1; @@ -360,15 +377,18 @@ perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, int dirfd, const char *nam return 0; } -static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias, - int dirfd, const char *name) +static int perf_pmu__parse_snapshot(struct perf_pmu *pmu, struct perf_pmu_alias *alias) { char path[PATH_MAX]; + size_t len; int fd; - scnprintf(path, PATH_MAX, "%s.snapshot", name); + len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path)); + if (!len) + return 0; + scnprintf(path + len, sizeof(path) - len, "%s/%s.snapshot", pmu->name, alias->name); - fd = openat(dirfd, path, O_RDONLY); + fd = open(path, O_RDONLY); if (fd == -1) return -1; @@ -429,32 +449,52 @@ static bool assign_str(const char *name, const char *field, char **old_str, return true; } +static void read_alias_info(struct perf_pmu *pmu, struct perf_pmu_alias *alias) +{ + if (!alias->from_sysfs || alias->info_loaded) + return; + + /* + * load unit name and scale if available + */ + perf_pmu__parse_unit(pmu, alias); + perf_pmu__parse_scale(pmu, alias); + perf_pmu__parse_per_pkg(pmu, alias); + perf_pmu__parse_snapshot(pmu, alias); +} + +struct update_alias_data { + struct perf_pmu *pmu; + struct perf_pmu_alias *alias; +}; + static int update_alias(const struct pmu_event *pe, const struct pmu_events_table *table __maybe_unused, void *vdata) { - struct perf_pmu_alias *alias = vdata; + struct update_alias_data *data = vdata; int ret = 0; - assign_str(pe->name, "desc", &alias->desc, pe->desc); - assign_str(pe->name, "long_desc", &alias->long_desc, pe->long_desc); - assign_str(pe->name, "topic", &alias->topic, pe->topic); - alias->per_pkg = pe->perpkg; - if (assign_str(pe->name, "value", &alias->str, pe->event)) { - parse_events_terms__purge(&alias->terms); - ret = parse_events_terms(&alias->terms, pe->event, /*input=*/NULL); + read_alias_info(data->pmu, data->alias); + assign_str(pe->name, "desc", &data->alias->desc, pe->desc); + assign_str(pe->name, "long_desc", &data->alias->long_desc, pe->long_desc); + assign_str(pe->name, "topic", &data->alias->topic, pe->topic); + data->alias->per_pkg = pe->perpkg; + if (assign_str(pe->name, "value", &data->alias->str, pe->event)) { + parse_events_terms__purge(&data->alias->terms); + ret = parse_events_terms(&data->alias->terms, pe->event, /*input=*/NULL); } if (!ret && pe->unit) { char *unit; - ret = perf_pmu__convert_scale(pe->unit, &unit, &alias->scale); + ret = perf_pmu__convert_scale(pe->unit, &unit, &data->alias->scale); if (!ret) - snprintf(alias->unit, sizeof(alias->unit), "%s", unit); + snprintf(data->alias->unit, sizeof(data->alias->unit), "%s", unit); } return ret; } -static int perf_pmu__new_alias(struct perf_pmu *pmu, int dirfd, const char *name, +static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name, const char *desc, const char *val, FILE *val_fd, const struct pmu_event *pe) { @@ -498,16 +538,6 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, int dirfd, const char *name } alias->name = strdup(name); - if (dirfd >= 0) { - /* - * load unit name and scale if available - */ - perf_pmu__parse_unit(alias, dirfd, name); - perf_pmu__parse_scale(alias, dirfd, name); - perf_pmu__parse_per_pkg(alias, dirfd, name); - perf_pmu__parse_snapshot(alias, dirfd, name); - } - alias->desc = desc ? strdup(desc) : NULL; alias->long_desc = long_desc ? strdup(long_desc) : desc ? strdup(desc) : NULL; @@ -522,9 +552,15 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, int dirfd, const char *name } if (!pe) { /* Update an event from sysfs with json data. */ + struct update_alias_data data = { + .pmu = pmu, + .alias = alias, + }; + + alias->from_sysfs = true; if (pmu->events_table) { if (pmu_events_table__find_event(pmu->events_table, pmu, name, - update_alias, alias) == 0) + update_alias, &data) == 0) pmu->loaded_json_aliases++; } } @@ -612,7 +648,7 @@ static int pmu_aliases_parse(struct perf_pmu *pmu, int dirfd) continue; } - if (perf_pmu__new_alias(pmu, dirfd, name, /*desc=*/ NULL, + if (perf_pmu__new_alias(pmu, name, /*desc=*/ NULL, /*val=*/ NULL, file, /*pe=*/ NULL) < 0) pr_debug("Cannot set up %s\n", name); fclose(file); @@ -865,7 +901,7 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe, { struct perf_pmu *pmu = vdata; - perf_pmu__new_alias(pmu, -1, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL, pe); + perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL, pe); return 0; } @@ -901,7 +937,7 @@ static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe, if (!strcmp(pmu->id, pe->compat) && pmu_uncore_alias_match(pe->pmu, pmu->name)) { - perf_pmu__new_alias(pmu, -1, + perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, @@ -1417,11 +1453,13 @@ static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu, } -static int check_info_data(struct perf_pmu_alias *alias, +static int check_info_data(struct perf_pmu *pmu, + struct perf_pmu_alias *alias, struct perf_pmu_info *info, struct parse_events_error *err, int column) { + read_alias_info(pmu, alias); /* * Only one term in event definition can * define unit, scale and snapshot, fail @@ -1491,7 +1529,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms, return ret; } - ret = check_info_data(alias, info, err, term->err_term); + ret = check_info_data(pmu, alias, info, err, term->err_term); if (ret) return ret;