Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752594AbdIVQiw (ORCPT ); Fri, 22 Sep 2017 12:38:52 -0400 Received: from terminus.zytor.com ([65.50.211.136]:44769 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752358AbdIVQit (ORCPT ); Fri, 22 Sep 2017 12:38:49 -0400 Date: Fri, 22 Sep 2017 09:35:28 -0700 From: tip-bot for Kan Liang Message-ID: Cc: kan.liang@intel.com, namhyung@kernel.org, tglx@linutronix.de, ak@linux.intel.com, lukasz.odzioba@intel.com, linux-kernel@vger.kernel.org, peterz@infradead.org, hpa@zytor.com, acme@redhat.com, jolsa@kernel.org, adrian.hunter@intel.com, mingo@kernel.org Reply-To: peterz@infradead.org, linux-kernel@vger.kernel.org, lukasz.odzioba@intel.com, ak@linux.intel.com, acme@redhat.com, hpa@zytor.com, jolsa@kernel.org, mingo@kernel.org, adrian.hunter@intel.com, kan.liang@intel.com, tglx@linutronix.de, namhyung@kernel.org In-Reply-To: <1504806954-150842-3-git-send-email-kan.liang@intel.com> References: <1504806954-150842-3-git-send-email-kan.liang@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf tools: Use scandir() to replace readdir() Git-Commit-ID: ecdad24d7a4480c9af0ff6dbe00ac8bbae720d19 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3329 Lines: 103 Commit-ID: ecdad24d7a4480c9af0ff6dbe00ac8bbae720d19 Gitweb: http://git.kernel.org/tip/ecdad24d7a4480c9af0ff6dbe00ac8bbae720d19 Author: Kan Liang AuthorDate: Thu, 7 Sep 2017 10:55:46 -0700 Committer: Arnaldo Carvalho de Melo CommitDate: Wed, 13 Sep 2017 09:49:15 -0300 perf tools: Use scandir() to replace readdir() In perf_event__synthesize_threads() perf goes through all proc files serially by readdir. scandir() does a snapshoot of /proc, which is multithreading friendly. It's possible that some threads which are added during event synthesize. But the number of lost threads should be small. They should not impact the final analysis. Signed-off-by: Kan Liang Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Lukasz Odzioba Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1504806954-150842-3-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.c | 45 +++++++++++++++++++++++++-------------------- 1 file changed, 25 insertions(+), 20 deletions(-) diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 1c905ba..17c21ea 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -683,12 +683,14 @@ int perf_event__synthesize_threads(struct perf_tool *tool, bool mmap_data, unsigned int proc_map_timeout) { - DIR *proc; - char proc_path[PATH_MAX]; - struct dirent *dirent; union perf_event *comm_event, *mmap_event, *fork_event; union perf_event *namespaces_event; + char proc_path[PATH_MAX]; + struct dirent **dirent; int err = -1; + char *end; + pid_t pid; + int n, i; if (machine__is_default_guest(machine)) return 0; @@ -712,29 +714,32 @@ int perf_event__synthesize_threads(struct perf_tool *tool, goto out_free_fork; snprintf(proc_path, sizeof(proc_path), "%s/proc", machine->root_dir); - proc = opendir(proc_path); + n = scandir(proc_path, &dirent, 0, alphasort); - if (proc == NULL) + if (n < 0) goto out_free_namespaces; - while ((dirent = readdir(proc)) != NULL) { - char *end; - pid_t pid = strtol(dirent->d_name, &end, 10); - - if (*end) /* only interested in proper numerical dirents */ + for (i = 0; i < n; i++) { + if (!isdigit(dirent[i]->d_name[0])) continue; - /* - * We may race with exiting thread, so don't stop just because - * one thread couldn't be synthesized. - */ - __event__synthesize_thread(comm_event, mmap_event, fork_event, - namespaces_event, pid, 1, process, - tool, machine, mmap_data, - proc_map_timeout); - } + pid = (pid_t)strtol(dirent[i]->d_name, &end, 10); + /* only interested in proper numerical dirents */ + if (!*end) { + /* + * We may race with exiting thread, so don't stop just because + * one thread couldn't be synthesized. + */ + __event__synthesize_thread(comm_event, mmap_event, fork_event, + namespaces_event, pid, 1, process, + tool, machine, mmap_data, + proc_map_timeout); + } + free(dirent[i]); + } + free(dirent); err = 0; - closedir(proc); + out_free_namespaces: free(namespaces_event); out_free_fork: