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>

1 files changed, 7 insertions, 25 deletions

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 8bd5ca2d2f28..3b56aebb1f4b 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);