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: Arnaldo 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: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0345aad..30b83de 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -203,46 +203,48 @@
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;
+ return 0;
}
- if (read(fd, bf, sizeof(bf)) < 0) {
- fprintf(stderr, "couldn't read %s\n", filename);
- exit(EXIT_FAILURE);
- }
- 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)
- goto out_failure;
- size = sep - field;
- memcpy(comm_ev.comm, field, size++);
+ while (!comm_ev.comm[0] || !comm_ev.pid) {
+ if (fgets(bf, sizeof(bf), fp) == NULL)
+ goto out_failure;
- 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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();