perf tools: Fix thread comm resolution in perf sched

This reverts commit 9a92b479b2f088ee2d3194243f4c8e59b1b8c9c2 ("perf
tools: Improve thread comm resolution in perf sched") and fixes the
real bug.

The bug was elsewhere:

We are failing to resolve thread names in perf sched because the
table of threads we are building, on top of comm events, has a per
process granularity. But perf sched, unlike the other perf tools,
needs a per thread granularity as we are profiling every tasks
individually.

So fix it by building our threads table using the tid instead of
the pid as the thread identifier.

v2: Revert the previous fix - it is not really needed

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1255028657-11158-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 7 insertions, 28 deletions

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 8bd5ca2..3b56aeb 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -6,17 +6,15 @@
 #include "util.h"
 #include "debug.h"
 
-static struct thread *thread__new(pid_t pid, int set_comm)
+static struct thread *thread__new(pid_t pid)
 {
 	struct thread *self = calloc(1, sizeof(*self));
 
 	if (self != NULL) {
 		self->pid = pid;
-		if (set_comm) {
-			self->comm = malloc(32);
-			if (self->comm)
-				snprintf(self->comm, 32, ":%d", self->pid);
-		}
+		self->comm = malloc(32);
+		if (self->comm)
+			snprintf(self->comm, 32, ":%d", self->pid);
 		self->maps = RB_ROOT;
 		INIT_LIST_HEAD(&self->removed_maps);
 	}
@@ -52,10 +50,8 @@ static size_t thread__fprintf(struct thread *self, FILE *fp)
 	return ret;
 }
 
-static struct thread *
-__threads__findnew(pid_t pid, struct rb_root *threads,
-		   struct thread **last_match,
-		   int set_comm)
+struct thread *
+threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
 {
 	struct rb_node **p = &threads->rb_node;
 	struct rb_node *parent = NULL;
@@ -84,8 +80,7 @@ __threads__findnew(pid_t pid, struct rb_root *threads,
 			p = &(*p)->rb_right;
 	}
 
-	th = thread__new(pid, set_comm);
-
+	th = thread__new(pid);
 	if (th != NULL) {
 		rb_link_node(&th->rb_node, parent, p);
 		rb_insert_color(&th->rb_node, threads);
@@ -96,19 +91,6 @@ __threads__findnew(pid_t pid, struct rb_root *threads,
 }
 
 struct thread *
-threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
-{
-	return __threads__findnew(pid, threads, last_match, 1);
-}
-
-struct thread *
-threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
-			struct thread **last_match)
-{
-	return __threads__findnew(pid, threads, last_match, 0);
-}
-
-struct thread *
 register_idle_thread(struct rb_root *threads, struct thread **last_match)
 {
 	struct thread *thread = threads__findnew(0, threads, last_match);
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 75bc843..845d9b6 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -18,9 +18,6 @@ int thread__set_comm(struct thread *self, const char *comm);
 struct thread *
 threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match);
 struct thread *
-threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
-			struct thread **last_match);
-struct thread *
 register_idle_thread(struct rb_root *threads, struct thread **last_match);
 void thread__insert_map(struct thread *self, struct map *map);
 int thread__fork(struct thread *self, struct thread *parent);