From f5faf726184a6a5ca1735f610cb97e509fce33e2 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 22 Dec 2011 11:30:02 -0700 Subject: perf tools: Look up thread names for system wide profiling This handles multithreaded processes with named threads when doing system wide profiling: the comm for each thread is looked up allowing them to be different from the thread group leader. v2: - fixed sizeof arg to perf_event__get_comm_tgid Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1324578603-12762-3-git-send-email-dsahern@gmail.com Signed-off-by: David Ahern Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.c | 75 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 53 insertions(+), 22 deletions(-) (limited to 'tools') diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index a5787260181a..73ddaf06b8e7 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -43,37 +43,27 @@ static struct perf_sample synth_sample = { .period = 1, }; -static pid_t perf_event__synthesize_comm(struct perf_tool *tool, - union perf_event *event, pid_t pid, - int full, perf_event__handler_t process, - struct machine *machine) +static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len) { char filename[PATH_MAX]; char bf[BUFSIZ]; FILE *fp; size_t size = 0; - DIR *tasks; - struct dirent dirent, *next; - pid_t tgid = 0; + pid_t tgid = -1; snprintf(filename, sizeof(filename), "/proc/%d/status", pid); fp = fopen(filename, "r"); if (fp == NULL) { -out_race: - /* - * We raced with a task exiting - just return: - */ pr_debug("couldn't open %s\n", filename); return 0; } - memset(&event->comm, 0, sizeof(event->comm)); - - while (!event->comm.comm[0] || !event->comm.pid) { + while (!comm[0] || (tgid < 0)) { if (fgets(bf, sizeof(bf), fp) == NULL) { - pr_warning("couldn't get COMM and pgid, malformed %s\n", filename); - goto out; + pr_warning("couldn't get COMM and pgid, malformed %s\n", + filename); + break; } if (memcmp(bf, "Name:", 5) == 0) { @@ -81,16 +71,46 @@ out_race: while (*name && isspace(*name)) ++name; size = strlen(name) - 1; - memcpy(event->comm.comm, name, size++); + if (size >= len) + size = len - 1; + memcpy(comm, name, size); + } else if (memcmp(bf, "Tgid:", 5) == 0) { char *tgids = bf + 5; while (*tgids && isspace(*tgids)) ++tgids; - tgid = event->comm.pid = atoi(tgids); + tgid = atoi(tgids); } } + fclose(fp); + + return tgid; +} + +static pid_t perf_event__synthesize_comm(struct perf_tool *tool, + union perf_event *event, pid_t pid, + int full, + perf_event__handler_t process, + struct machine *machine) +{ + char filename[PATH_MAX]; + size_t size; + DIR *tasks; + struct dirent dirent, *next; + pid_t tgid; + + memset(&event->comm, 0, sizeof(event->comm)); + + tgid = perf_event__get_comm_tgid(pid, event->comm.comm, + sizeof(event->comm.comm)); + if (tgid < 0) + goto out; + + event->comm.pid = tgid; event->comm.header.type = PERF_RECORD_COMM; + + size = strlen(event->comm.comm) + 1; size = ALIGN(size, sizeof(u64)); memset(event->comm.comm + size, 0, machine->id_hdr_size); event->comm.header.size = (sizeof(event->comm) - @@ -106,8 +126,10 @@ out_race: snprintf(filename, sizeof(filename), "/proc/%d/task", pid); tasks = opendir(filename); - if (tasks == NULL) - goto out_race; + if (tasks == NULL) { + pr_debug("couldn't open %s\n", filename); + return 0; + } while (!readdir_r(tasks, &dirent, &next) && next) { char *end; @@ -115,6 +137,17 @@ out_race: if (*end) continue; + /* already have tgid; jut want to update the comm */ + (void) perf_event__get_comm_tgid(pid, event->comm.comm, + sizeof(event->comm.comm)); + + size = strlen(event->comm.comm) + 1; + size = ALIGN(size, sizeof(u64)); + memset(event->comm.comm + size, 0, machine->id_hdr_size); + event->comm.header.size = (sizeof(event->comm) - + (sizeof(event->comm.comm) - size) + + machine->id_hdr_size); + event->comm.tid = pid; process(tool, event, &synth_sample, machine); @@ -122,8 +155,6 @@ out_race: closedir(tasks); out: - fclose(fp); - return tgid; } -- cgit v1.2.3