From ecdad24d7a4480c9af0ff6dbe00ac8bbae720d19 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Thu, 7 Sep 2017 10:55:46 -0700 Subject: 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(-) (limited to 'tools') 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: -- cgit v1.1