Commit 2a8083f0 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by Ingo Molnar
Browse files

perf record: Fix .tid and .pid fill-in when synthesizing events 



Noticed when trying to record events for a firefox thread. We
were synthesizing both .tid and .pid with the pid passed via
--pid.

Fix it by reading /proc/PID/status and getting the tgid
to use in .pid, .tid gets the specified "pid".

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20090811192200.GF18061@ghostprotocols.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f64ccccb

tools/perf/builtin-record.c

+38 −33
Original line number Diff line number Diff line
@@ -203,46 +203,48 @@ static void sig_atexit(void) 
	kill(getpid(), signr);

}



static void pid_synthesize_comm_event(pid_t pid, int full)

static pid_t pid_synthesize_comm_event(pid_t pid, int full)

{

	struct comm_event comm_ev;

	char filename[PATH_MAX];

	char bf[BUFSIZ];

	int fd;

	size_t size;

	char *field, *sep;

	FILE *fp;

	size_t size = 0;

	DIR *tasks;

	struct dirent dirent, *next;

	pid_t tgid = 0;



	snprintf(filename, sizeof(filename), "/proc/%d/stat", pid);

	snprintf(filename, sizeof(filename), "/proc/%d/status", pid);



	fd = open(filename, O_RDONLY);

	if (fd < 0) {

	fp = fopen(filename, "r");

	if (fd == NULL) {

		/*

		 * We raced with a task exiting - just return:

		 */

		if (verbose)

			fprintf(stderr, "couldn't open %s\n", filename);

		return;

	}

	if (read(fd, bf, sizeof(bf)) < 0) {

		fprintf(stderr, "couldn't read %s\n", filename);

		exit(EXIT_FAILURE);

		return 0;

	}

	close(fd);



	/* 9027 (cat) R 6747 9027 6747 34816 9027 ... */

	memset(&comm_ev, 0, sizeof(comm_ev));

	field = strchr(bf, '(');

	if (field == NULL)

		goto out_failure;

	sep = strchr(++field, ')');

	if (sep == NULL)

	while (!comm_ev.comm[0] || !comm_ev.pid) {

		if (fgets(bf, sizeof(bf), fp) == NULL)

			goto out_failure;

	size = sep - field;

	memcpy(comm_ev.comm, field, size++);



	comm_ev.pid = pid;

		if (memcmp(bf, "Name:", 5) == 0) {

			char *name = bf + 5;

			while (*name && isspace(*name))

				++name;

			size = strlen(name) - 1;

			memcpy(comm_ev.comm, name, size++);

		} else if (memcmp(bf, "Tgid:", 5) == 0) {

			char *tgids = bf + 5;

			while (*tgids && isspace(*tgids))

				++tgids;

			tgid = comm_ev.pid = atoi(tgids);

		}

	}



	comm_ev.header.type = PERF_EVENT_COMM;

	size = ALIGN(size, sizeof(u64));

	comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
@@ -251,7 +253,7 @@ static void pid_synthesize_comm_event(pid_t pid, int full) 
		comm_ev.tid = pid;



		write_output(&comm_ev, comm_ev.header.size);

		return;

		goto out_fclose;

	}



	snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
@@ -268,7 +270,10 @@ static void pid_synthesize_comm_event(pid_t pid, int full) 
		write_output(&comm_ev, comm_ev.header.size);

	}

	closedir(tasks);

	return;



out_fclose:

	fclose(fp);

	return tgid;



out_failure:

	fprintf(stderr, "couldn't get COMM and pgid, malformed %s\n",
@@ -276,7 +281,7 @@ out_failure: 
	exit(EXIT_FAILURE);

}



static void pid_synthesize_mmap_samples(pid_t pid)

static void pid_synthesize_mmap_samples(pid_t pid, pid_t tgid)

{

	char filename[PATH_MAX];

	FILE *fp;
@@ -328,7 +333,7 @@ static void pid_synthesize_mmap_samples(pid_t pid) 
			mmap_ev.len -= mmap_ev.start;

			mmap_ev.header.size = (sizeof(mmap_ev) -

					       (sizeof(mmap_ev.filename) - size));

			mmap_ev.pid = pid;

			mmap_ev.pid = tgid;

			mmap_ev.tid = pid;



			write_output(&mmap_ev, mmap_ev.header.size);
@@ -347,14 +352,14 @@ static void synthesize_all(void) 


	while (!readdir_r(proc, &dirent, &next) && next) {

		char *end;

		pid_t pid;

		pid_t pid, tgid;



		pid = strtol(dirent.d_name, &end, 10);

		if (*end) /* only interested in proper numerical dirents */

			continue;



		pid_synthesize_comm_event(pid, 1);

		pid_synthesize_mmap_samples(pid);

		tgid = pid_synthesize_comm_event(pid, 1);

		pid_synthesize_mmap_samples(pid, tgid);

	}



	closedir(proc);
@@ -567,8 +572,8 @@ static int __cmd_record(int argc, const char **argv) 
		perf_header__write(header, output);



	if (!system_wide) {

		pid_synthesize_comm_event(pid, 0);

		pid_synthesize_mmap_samples(pid);

		pid_t tgid = pid_synthesize_comm_event(pid, 0);

		pid_synthesize_mmap_samples(pid, tgid);

	} else

		synthesize_all();

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