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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: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
David Ahern 2011-12-22 11:30:02 -07:00 committed by Arnaldo Carvalho de Melo
parent defd8d3877
commit f5faf72618
1 changed files with 53 additions and 22 deletions
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75
tools/perf/util/event.c
View File

@ -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 @@ out_race:
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 @@ out_race:
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 @@ out_race:
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 @@ out_race:
closedir(tasks);
out:
fclose(fp);
return tgid;
}