lkml.org 
[lkml]   [2009]   [Aug]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH tip 2/3] perf record: Fill .tid and .pid correctly 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".

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 71 +++++++++++++++++++++++--------------------
1 files changed, 38 insertions(+), 33 deletions(-)

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 @@ 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;
+ 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++);
-
- comm_ev.pid = pid;
+ while (!comm_ev.comm[0] || !comm_ev.pid) {
+ if (fgets(bf, sizeof(bf), fp) == NULL)
+ goto out_failure;
+
+ 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();

--
1.6.2.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2009-08-11 21:25    [W:1.921 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site