From patchwork Wed Nov 29 06:01:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ian Rogers X-Patchwork-Id: 13472216 X-Patchwork-Delegate: bpf@iogearbox.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="uspoxPX8" Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72EC81BC0 for ; Tue, 28 Nov 2023 22:02:20 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-db4004a8aa9so7330775276.1 for ; Tue, 28 Nov 2023 22:02:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1701237739; x=1701842539; darn=vger.kernel.org; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=T8ykSaAbLFyuzcPYepQRuQ5xp7FIWrmaxmvAYiTpoEM=; b=uspoxPX8E+ukWpbpDaIPltcSuLuYXkZjkyQAFnD+ZHlccd93ygNbhE26g8N6A4gGZz trPWszcg5+fakGMKJ+JFfhMMI4CN3LnxyRb/fYgJNWnTFEmTjgUcg0G+GprK510Yy3Xd 08AhJLv98drog7NjeiFW1WzE4hZeOG8BW1Y5C8ski6VCPzKnnBdjclcklHDBFqMTh43s zsorQtJWI5V+yphwovihsaN6UUnQOypJmvwifGk7w90+kKsc7xaK8pDO8RDweob5FO3X jVH8kgHR8Zzeb0YWDJpcaVTopuDEraS6pKdliysP9MenV4fiimta7aabEoSVfldTzCcq Kneg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701237739; x=1701842539; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=T8ykSaAbLFyuzcPYepQRuQ5xp7FIWrmaxmvAYiTpoEM=; b=KVS77OrUKNKZoRds1csTjUm0o2STk2q5XETdRws1IVWcJv5HajOdgLhz5qXb5hrc7G C3sAstVPleXUcRs8tGBtke8EgqqS/G7NlIYD1mlXKZBygsa4fBW9qjJWnpy+QjUW88WT IxWZ8Vb1eOtUKkP2PfAp7xNJ3pFJC610nmK/pAN55dwlK556tYlVIHCOjK3TAv5+X+3C 0sKWevu3QtVddQbOUBg6/swaEZ/zeTn6dWQpgmcp91JMobZuNm4/nglCmAIbOYSAy4wC hgYleSktGUc7SwVkHUY113fu0yLWM8JFD/AZz6PKtRFK+CPCoZepmpUScxs5PetmWPVB Q5OA== X-Gm-Message-State: AOJu0Yz+XvN5VYqqOoAYeGQO3T1J8lw+dxyha8O2zdMBIzRyTFFezdjh dTFeGjAMXW6a/ySSDGPWExmNYk5V+Tqt X-Google-Smtp-Source: AGHT+IGpkfJM/vGDzeJGawlB8gonUbNHatIumaAJ9ml4Cx9YmaCI6/1HJPOtb7yX5CQXz6dt/8yBM1CTLG9d X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:763b:80fa:23ca:96f8]) (user=irogers job=sendgmr) by 2002:a25:ca50:0:b0:daf:5d6b:ef39 with SMTP id a77-20020a25ca50000000b00daf5d6bef39mr547103ybg.12.1701237739607; Tue, 28 Nov 2023 22:02:19 -0800 (PST) Date: Tue, 28 Nov 2023 22:01:59 -0800 In-Reply-To: <20231129060211.1890454-1-irogers@google.com> Message-Id: <20231129060211.1890454-3-irogers@google.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231129060211.1890454-1-irogers@google.com> X-Mailer: git-send-email 2.43.0.rc1.413.gea7ed67945-goog Subject: [PATCH v1 02/14] libperf cpumap: Rename and prefer sysfs for perf_cpu_map__default_new From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Suzuki K Poulose , Mike Leach , James Clark , Leo Yan , John Garry , Will Deacon , Thomas Gleixner , Darren Hart , Davidlohr Bueso , " =?utf-8?q?Andr=C3=A9_Almeida?= " , Kan Liang , K Prateek Nayak , Sean Christopherson , Paolo Bonzini , Kajol Jain , Athira Rajeev , Andrew Jones , Alexandre Ghiti , Atish Patra , "Steinar H. Gunderson" , Yang Jihong , Yang Li , Changbin Du , Sandipan Das , Ravi Bangoria , Paran Lee , Nick Desaulniers , Huacai Chen , Yanteng Si , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org Rename perf_cpu_map__default_new to perf_cpu_map__new_online_cpus to better indicate what the implementation does. Read the online CPUs from /sys/devices/system/cpu/online first before using sysconf as sysconf can't accurately configure holes in the CPU map. If sysconf is used, warn when the configured and online processors disagree. When reading from a file, if the read doesn't yield a CPU map then return an empty map rather than the default online. This avoids recursion but also better yields being able to detect failures. Add more comments. Signed-off-by: Ian Rogers Reviewed-by: James Clark --- tools/lib/perf/cpumap.c | 59 +++++++++++++++++----------- tools/lib/perf/include/perf/cpumap.h | 15 ++++++- tools/lib/perf/libperf.map | 2 +- tools/lib/perf/tests/test-cpumap.c | 2 +- 4 files changed, 51 insertions(+), 27 deletions(-) diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c index 2bd6aba3d8c9..463ca8b37d45 100644 --- a/tools/lib/perf/cpumap.c +++ b/tools/lib/perf/cpumap.c @@ -9,6 +9,7 @@ #include #include #include +#include "internal.h" void perf_cpu_map__set_nr(struct perf_cpu_map *map, int nr_cpus) { @@ -66,15 +67,21 @@ void perf_cpu_map__put(struct perf_cpu_map *map) } } -static struct perf_cpu_map *cpu_map__default_new(void) +static struct perf_cpu_map *cpu_map__new_sysconf(void) { struct perf_cpu_map *cpus; - int nr_cpus; + int nr_cpus, nr_cpus_conf; nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); if (nr_cpus < 0) return NULL; + nr_cpus_conf = sysconf(_SC_NPROCESSORS_CONF); + if (nr_cpus != nr_cpus_conf) { + pr_warning("Number of online CPUs (%d) differs from the number configured (%d) the CPU map will only cover the first %d CPUs.", + nr_cpus, nr_cpus_conf, nr_cpus); + } + cpus = perf_cpu_map__alloc(nr_cpus); if (cpus != NULL) { int i; @@ -86,9 +93,27 @@ static struct perf_cpu_map *cpu_map__default_new(void) return cpus; } -struct perf_cpu_map *perf_cpu_map__default_new(void) +static struct perf_cpu_map *cpu_map__new_syfs_online(void) { - return cpu_map__default_new(); + struct perf_cpu_map *cpus = NULL; + FILE *onlnf; + + onlnf = fopen("/sys/devices/system/cpu/online", "r"); + if (onlnf) { + cpus = perf_cpu_map__read(onlnf); + fclose(onlnf); + } + return cpus; +} + +struct perf_cpu_map *perf_cpu_map__new_online_cpus(void) +{ + struct perf_cpu_map *cpus = cpu_map__new_syfs_online(); + + if (cpus) + return cpus; + + return cpu_map__new_sysconf(); } @@ -180,27 +205,11 @@ struct perf_cpu_map *perf_cpu_map__read(FILE *file) if (nr_cpus > 0) cpus = cpu_map__trim_new(nr_cpus, tmp_cpus); - else - cpus = cpu_map__default_new(); out_free_tmp: free(tmp_cpus); return cpus; } -static struct perf_cpu_map *cpu_map__read_all_cpu_map(void) -{ - struct perf_cpu_map *cpus = NULL; - FILE *onlnf; - - onlnf = fopen("/sys/devices/system/cpu/online", "r"); - if (!onlnf) - return cpu_map__default_new(); - - cpus = perf_cpu_map__read(onlnf); - fclose(onlnf); - return cpus; -} - struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) { struct perf_cpu_map *cpus = NULL; @@ -211,7 +220,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) int max_entries = 0; if (!cpu_list) - return cpu_map__read_all_cpu_map(); + return perf_cpu_map__new_online_cpus(); /* * must handle the case of empty cpumap to cover @@ -268,9 +277,11 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) if (nr_cpus > 0) cpus = cpu_map__trim_new(nr_cpus, tmp_cpus); - else if (*cpu_list != '\0') - cpus = cpu_map__default_new(); - else + else if (*cpu_list != '\0') { + pr_warning("Unexpected characters at end of cpu list ('%s'), using online CPUs.", + cpu_list); + cpus = perf_cpu_map__new_online_cpus(); + } else cpus = perf_cpu_map__new_any_cpu(); invalid: free(tmp_cpus); diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h index d0bf218ada11..b24bd8b8f34e 100644 --- a/tools/lib/perf/include/perf/cpumap.h +++ b/tools/lib/perf/include/perf/cpumap.h @@ -22,7 +22,20 @@ struct perf_cpu_map; * perf_cpu_map__new_any_cpu - a map with a singular "any CPU"/dummy -1 value. */ LIBPERF_API struct perf_cpu_map *perf_cpu_map__new_any_cpu(void); -LIBPERF_API struct perf_cpu_map *perf_cpu_map__default_new(void); +/** + * perf_cpu_map__new_online_cpus - a map read from + * /sys/devices/system/cpu/online if + * available. If reading wasn't possible a map + * is created using the online processors + * assuming the first 'n' processors are all + * online. + */ +LIBPERF_API struct perf_cpu_map *perf_cpu_map__new_online_cpus(void); +/** + * perf_cpu_map__new - create a map from the given cpu_list such as "0-7". If no + * cpu_list argument is provided then + * perf_cpu_map__new_online_cpus is returned. + */ LIBPERF_API struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list); LIBPERF_API struct perf_cpu_map *perf_cpu_map__read(FILE *file); LIBPERF_API struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map); diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map index a8ff64baea3e..8a71f841498e 100644 --- a/tools/lib/perf/libperf.map +++ b/tools/lib/perf/libperf.map @@ -2,7 +2,7 @@ LIBPERF_0.0.1 { global: libperf_init; perf_cpu_map__new_any_cpu; - perf_cpu_map__default_new; + perf_cpu_map__new_online_cpus; perf_cpu_map__get; perf_cpu_map__put; perf_cpu_map__new; diff --git a/tools/lib/perf/tests/test-cpumap.c b/tools/lib/perf/tests/test-cpumap.c index 2c359bdb951e..c998b1dae863 100644 --- a/tools/lib/perf/tests/test-cpumap.c +++ b/tools/lib/perf/tests/test-cpumap.c @@ -29,7 +29,7 @@ int test_cpumap(int argc, char **argv) perf_cpu_map__put(cpus); perf_cpu_map__put(cpus); - cpus = perf_cpu_map__default_new(); + cpus = perf_cpu_map__new_online_cpus(); if (!cpus) return -1;