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Commit f5faf726 authored by David Ahern's avatar David Ahern Committed by Arnaldo Carvalho de Melo
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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 <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-3-git-send-email-dsahern@gmail.com


Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent defd8d38

tools/perf/util/event.c

+53 −22
Original line number Diff line number Diff line
@@ -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 @@ static pid_t perf_event__synthesize_comm(struct perf_tool *tool, 
			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 @@ static pid_t perf_event__synthesize_comm(struct perf_tool *tool, 
	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 @@ static pid_t perf_event__synthesize_comm(struct perf_tool *tool, 
		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 @@ static pid_t perf_event__synthesize_comm(struct perf_tool *tool, 


	closedir(tasks);

out:

	fclose(fp);



	return tgid;

}