From nobody Fri Feb 13 12:30:09 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4608CE7A81 for ; Mon, 25 Sep 2023 06:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232051AbjIYGYy (ORCPT ); Mon, 25 Sep 2023 02:24:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232348AbjIYGYl (ORCPT ); Mon, 25 Sep 2023 02:24:41 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFBC5E5C for ; Sun, 24 Sep 2023 23:24:29 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-59beea5ce93so163511067b3.0 for ; Sun, 24 Sep 2023 23:24:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695623068; x=1696227868; darn=vger.kernel.org; h=to:from:subject:mime-version:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=66Z0VZtyUYys0PdxQ7OWuDfLkowOhrBXRt1ENvc5Q34=; b=jB3XHqWs6yBx5WFm/ZvWhL3vJyZ1RrstswS1CHBYQVjA+5yQleA1IiP+oAmzBPQSL2 7xD4uw80BXZGQgLJcxx9rIGZSU+SQZSzzH4ODoMx4WwCI5YSs2c+bSHUbtOPU6lgz97r +VEiygMmgyY+sIEOkVBXK+piu9eAoY0UVApJF8AnDzsDgRx5kY3SnpKNBsqzziszXEoo p41MadR22mNGWgqUUvIHLAXSF8xbyGK3q38etf++L7EyOxPAxaWRHwel0as+IL5K7nlp C1MngSYx50qnvyzCSAPl8gJNIlhygFOL5yO8kB10lTaVjTAbUattbnOIJbkDWH0W6/be /L5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695623068; x=1696227868; h=to:from:subject:mime-version:message-id:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=66Z0VZtyUYys0PdxQ7OWuDfLkowOhrBXRt1ENvc5Q34=; b=o3b4hXlZMvWeG4MeqJ3ssKYbgv/cMrKdFLlrgC10tW+vOHp4fi1wfioHA74r/9tvB8 R9pb8nIDbzqgSRnVmB5zEh3xG4gPLfj9ynhDNrhLQclowlS3xRFdPx2mP2KrOu+6cvXC hacYIGMVpLzvWQSGOaUeXNd/clTBF5KkZgp172wCtDFa8FcTqS+kUrzZDRT6/AV+MYYr ZTtjet5PKmQv1DgRXjZKk3L+79SA0Q33/otMkvN1wHKs4N4Dg14U6Hsd+DH1Z1BtXqGv ReVFVJT+Vxs0lJVAC2oQgrUGEli3aXQMnvcVk5c/HDUMkZtbVU9yGaIe257+Dn5lAp9Y p8Sg== X-Gm-Message-State: AOJu0Ywn9ZNBWfw/qwmSIB1IbCZ4qG08rFZeDT3j69hq2E+Yp8t2+qmL tyLEQ9q4wXBtGD2t6USOapOQ7TfFsTXQ X-Google-Smtp-Source: AGHT+IFRzYD0MmvHuqoLSZgcjVTtth3pN3U1O0gxgnvc+hmvYLHm63JgsQnLUn8tN4x1rYF1tgr5YJW0Dle/ X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:a8a5:e1ea:d5a4:5980]) (user=irogers job=sendgmr) by 2002:a81:4c90:0:b0:59e:8f97:27ed with SMTP id z138-20020a814c90000000b0059e8f9727edmr156885ywa.1.1695623068705; Sun, 24 Sep 2023 23:24:28 -0700 (PDT) Date: Sun, 24 Sep 2023 23:23:23 -0700 Message-Id: <20230925062323.840799-1-irogers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Subject: [PATCH v1] perf pmus: Make PMU alias name loading lazy From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Leo Yan , Ravi Bangoria , James Clark , Kan Liang , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" PMU alias names were computed when the first perf_pmu is created, scanning all PMUs in event sources for a file called alias that generally doesn't exist. Switch to trying to load the file when all PMU related files are loaded in lookup. This would cause a PMU name lookup of an alias name to fail if no PMUs were loaded, so in that case all PMUs are loaded and the find repeated. The overhead is similar but in the (very) general case not all PMUs are scanned for the alias file. As the overhead occurs once per invocation it doesn't show in perf bench internals pmu-scan. On a tigerlake machine, the number of openat system calls for an event of cpu/cycles/ with perf stat reduces from 94 to 69 (ie 25 fewer openat calls). Signed-off-by: Ian Rogers Acked-by: Namhyung Kim --- tools/perf/arch/x86/util/pmu.c | 139 --------------------------------- tools/perf/util/pmu.c | 39 ++++----- tools/perf/util/pmu.h | 2 - tools/perf/util/pmus.c | 10 +++ 4 files changed, 31 insertions(+), 159 deletions(-) diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c index f428cffb0378..8b53ca468a50 100644 --- a/tools/perf/arch/x86/util/pmu.c +++ b/tools/perf/arch/x86/util/pmu.c @@ -17,15 +17,6 @@ #include "../../../util/pmus.h" #include "env.h" =20 -struct pmu_alias { - char *name; - char *alias; - struct list_head list; -}; - -static LIST_HEAD(pmu_alias_name_list); -static bool cached_list; - struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu = __maybe_unused) { #ifdef HAVE_AUXTRACE_SUPPORT @@ -41,136 +32,6 @@ struct perf_event_attr *perf_pmu__get_default_config(st= ruct perf_pmu *pmu __mayb return NULL; } =20 -static void pmu_alias__delete(struct pmu_alias *pmu_alias) -{ - if (!pmu_alias) - return; - - zfree(&pmu_alias->name); - zfree(&pmu_alias->alias); - free(pmu_alias); -} - -static struct pmu_alias *pmu_alias__new(char *name, char *alias) -{ - struct pmu_alias *pmu_alias =3D zalloc(sizeof(*pmu_alias)); - - if (pmu_alias) { - pmu_alias->name =3D strdup(name); - if (!pmu_alias->name) - goto out_delete; - - pmu_alias->alias =3D strdup(alias); - if (!pmu_alias->alias) - goto out_delete; - } - return pmu_alias; - -out_delete: - pmu_alias__delete(pmu_alias); - return NULL; -} - -static int setup_pmu_alias_list(void) -{ - int fd, dirfd; - DIR *dir; - struct dirent *dent; - struct pmu_alias *pmu_alias; - char buf[MAX_PMU_NAME_LEN]; - FILE *file; - int ret =3D -ENOMEM; - - dirfd =3D perf_pmu__event_source_devices_fd(); - if (dirfd < 0) - return -1; - - dir =3D fdopendir(dirfd); - if (!dir) - return -errno; - - while ((dent =3D readdir(dir))) { - if (!strcmp(dent->d_name, ".") || - !strcmp(dent->d_name, "..")) - continue; - - fd =3D perf_pmu__pathname_fd(dirfd, dent->d_name, "alias", O_RDONLY); - if (fd < 0) - continue; - - file =3D fdopen(fd, "r"); - if (!file) - continue; - - if (!fgets(buf, sizeof(buf), file)) { - fclose(file); - continue; - } - - fclose(file); - - /* Remove the last '\n' */ - buf[strlen(buf) - 1] =3D 0; - - pmu_alias =3D pmu_alias__new(dent->d_name, buf); - if (!pmu_alias) - goto close_dir; - - list_add_tail(&pmu_alias->list, &pmu_alias_name_list); - } - - ret =3D 0; - -close_dir: - closedir(dir); - return ret; -} - -static const char *__pmu_find_real_name(const char *name) -{ - struct pmu_alias *pmu_alias; - - list_for_each_entry(pmu_alias, &pmu_alias_name_list, list) { - if (!strcmp(name, pmu_alias->alias)) - return pmu_alias->name; - } - - return name; -} - -const char *pmu_find_real_name(const char *name) -{ - if (cached_list) - return __pmu_find_real_name(name); - - setup_pmu_alias_list(); - cached_list =3D true; - - return __pmu_find_real_name(name); -} - -static const char *__pmu_find_alias_name(const char *name) -{ - struct pmu_alias *pmu_alias; - - list_for_each_entry(pmu_alias, &pmu_alias_name_list, list) { - if (!strcmp(name, pmu_alias->name)) - return pmu_alias->alias; - } - return NULL; -} - -const char *pmu_find_alias_name(const char *name) -{ - if (cached_list) - return __pmu_find_alias_name(name); - - setup_pmu_alias_list(); - cached_list =3D true; - - return __pmu_find_alias_name(name); -} - int perf_pmus__num_mem_pmus(void) { /* AMD uses IBS OP pmu and not a core PMU for perf mem/c2c */ diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 0d81c059c91c..0f5c6ed257a8 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -937,16 +937,27 @@ perf_pmu__get_default_config(struct perf_pmu *pmu __m= aybe_unused) return NULL; } =20 -const char * __weak -pmu_find_real_name(const char *name) +static char *pmu_find_alias_name(struct perf_pmu *pmu, int dirfd) { - return name; -} + FILE *file =3D perf_pmu__open_file_at(pmu, dirfd, "alias"); + char *line =3D NULL; + size_t line_len =3D 0; + ssize_t ret; =20 -const char * __weak -pmu_find_alias_name(const char *name __maybe_unused) -{ - return NULL; + if (!file) + return NULL; + + ret =3D getline(&line, &line_len, file); + if (ret < 0) { + fclose(file); + return NULL; + } + /* Remove trailing newline. */ + if (ret > 0 && line[ret - 1] =3D=3D '\n') + line[--ret] =3D '\0'; + + fclose(file); + return line; } =20 static int pmu_max_precise(int dirfd, struct perf_pmu *pmu) @@ -957,12 +968,10 @@ static int pmu_max_precise(int dirfd, struct perf_pmu= *pmu) return max_precise; } =20 -struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *lookup_name) +struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *name) { struct perf_pmu *pmu; __u32 type; - const char *name =3D pmu_find_real_name(lookup_name); - const char *alias_name; =20 pmu =3D zalloc(sizeof(*pmu)); if (!pmu) @@ -995,18 +1004,12 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *= pmus, int dirfd, const char pmu->is_core =3D is_pmu_core(name); pmu->cpus =3D pmu_cpumask(dirfd, name, pmu->is_core); =20 - alias_name =3D pmu_find_alias_name(name); - if (alias_name) { - pmu->alias_name =3D strdup(alias_name); - if (!pmu->alias_name) - goto err; - } - pmu->type =3D type; pmu->is_uncore =3D pmu_is_uncore(dirfd, name); if (pmu->is_uncore) pmu->id =3D pmu_id(name); pmu->max_precise =3D pmu_max_precise(dirfd, pmu); + pmu->alias_name =3D pmu_find_alias_name(pmu, dirfd); pmu->events_table =3D perf_pmu__find_events_table(pmu); pmu_add_sys_aliases(pmu); list_add_tail(&pmu->list, pmus); diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 04b317b17d66..bc807729a7cd 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -251,8 +251,6 @@ void perf_pmu__warn_invalid_formats(struct perf_pmu *pm= u); =20 int perf_pmu__match(const char *pattern, const char *name, const char *tok= ); =20 -const char *pmu_find_real_name(const char *name); -const char *pmu_find_alias_name(const char *name); double perf_pmu__cpu_slots_per_cycle(void); int perf_pmu__event_source_devices_scnprintf(char *pathname, size_t size); int perf_pmu__pathname_scnprintf(char *buf, size_t size, diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index 64e798e68a2d..ce4931461741 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -37,6 +37,8 @@ static LIST_HEAD(other_pmus); static bool read_sysfs_core_pmus; static bool read_sysfs_all_pmus; =20 +static void pmu_read_sysfs(bool core_only); + int pmu_name_len_no_suffix(const char *str, unsigned long *num) { int orig_len, len; @@ -124,6 +126,14 @@ struct perf_pmu *perf_pmus__find(const char *name) pmu =3D perf_pmu__lookup(core_pmu ? &core_pmus : &other_pmus, dirfd, name= ); close(dirfd); =20 + if (!pmu) { + /* + * Looking up an inidividual PMU failed. This may mean name is + * an alias, so read the PMUs from sysfs and try to find again. + */ + pmu_read_sysfs(core_pmu); + pmu =3D pmu_find(name); + } return pmu; } =20 --=20 2.42.0.515.g380fc7ccd1-goog