From: Kan Liang <kan.li...@intel.com>
If user has zombie process, the perf record -u will error out.
Here is an example.
$ ./testd &
[1] 23796
$ sudo perf record -e cycles -u kan
Error:
The sys_perf_event_open() syscall returned with 3 (No such process) for
event (cycles).
/bin/dmesg may provide additional information.
No CONFIG_PERF_EVENTS=y kernel support configured?
The source code of testd is as below.
int main() {
if (fork())
{
while (1);
}
return 0;
}
Zombie process is dead process. It is meaningless to profile it.
It's better to ignore it for user profile.
Signed-off-by: Kan Liang <kan.li...@intel.com>
---
tools/perf/util/thread_map.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index 40585f5..4643b69 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -89,6 +89,39 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
return threads;
}
+static bool is_zombie_process(pid_t pid)
+{
+ char filename[PATH_MAX];
+ char comm[PATH_MAX];
+ char bf[BUFSIZ];
+ char s_state;
+ int s_pid;
+ FILE *fp;
+ ssize_t n;
+
+ snprintf(filename, sizeof(filename), "/proc/%d/stat", pid);
+ fp = fopen(filename, "r");
+ if (!fp) {
+ pr_warning("couldn't open %s\n", filename);
+ return false;
+ }
+ if (fgets(bf, sizeof(bf), fp) == NULL) {
+ pr_warning("Couldn't read stat for pid %d\n", pid);
+ fclose(fp);
+ return false;
+ }
+ fclose(fp);
+
+ n = sscanf(bf, "%d %s %c ", &s_pid, comm, &s_state);
+ if (n < 3)
+ return false;
+
+ if (s_state == 'Z')
+ return true;
+
+ return false;
+}
+
struct thread_map *thread_map__new_by_uid(uid_t uid)
{
DIR *proc;
@@ -124,6 +157,9 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
if (st.st_uid != uid)
continue;
+ if (is_zombie_process(pid))
+ continue;
+
snprintf(path, sizeof(path), "/proc/%d/task", pid);
items = scandir(path, &namelist, filter, NULL);
if (items <= 0)
--
2.4.3
