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, 6 insertions, 40 deletions

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 25b91e78433..6b00529ce34 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -638,7 +638,7 @@ process_comm_event(event_t *event, unsigned long offset, unsigned long head)
 {
 	struct thread *thread;
 
-	thread = threads__findnew(event->comm.pid, &threads, &last_match);
+	thread = threads__findnew(event->comm.tid, &threads, &last_match);
 
 	dump_printf("%p [%p]: perf_event_comm: %s:%d\n",
 		(void *)(offset + head),
@@ -1034,36 +1034,6 @@ add_sched_in_event(struct work_atoms *atoms, u64 timestamp)
 	atoms->nb_atoms++;
 }
 
-static struct thread *
-threads__findnew_from_ctx(u32 pid, struct trace_switch_event *switch_event)
-{
-	struct thread *th;
-
-	th = threads__findnew_nocomm(pid, &threads, &last_match);
-	if (th->comm)
-		return th;
-
-	if (pid == switch_event->prev_pid)
-		thread__set_comm(th, switch_event->prev_comm);
-	else
-		thread__set_comm(th, switch_event->next_comm);
-	return th;
-}
-
-static struct thread *
-threads__findnew_from_wakeup(struct trace_wakeup_event *wakeup_event)
-{
-	struct thread *th;
-
-	th =  threads__findnew_nocomm(wakeup_event->pid, &threads, &last_match);
-	if (th->comm)
-		return th;
-
-	thread__set_comm(th, wakeup_event->comm);
-
-	return th;
-}
-
 static void
 latency_switch_event(struct trace_switch_event *switch_event,
 		     struct event *event __used,
@@ -1089,10 +1059,8 @@ latency_switch_event(struct trace_switch_event *switch_event,
 		die("hm, delta: %Ld < 0 ?\n", delta);
 
 
-	sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
-					      switch_event);
-	sched_in = threads__findnew_from_ctx(switch_event->next_pid,
-					     switch_event);
+	sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
+	sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
 
 	out_events = thread_atoms_search(&atom_root, sched_out, &cmp_pid);
 	if (!out_events) {
@@ -1158,7 +1126,7 @@ latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
 	if (!wakeup_event->success)
 		return;
 
-	wakee = threads__findnew_from_wakeup(wakeup_event);
+	wakee = threads__findnew(wakeup_event->pid, &threads, &last_match);
 	atoms = thread_atoms_search(&atom_root, wakee, &cmp_pid);
 	if (!atoms) {
 		thread_atoms_insert(wakee);
@@ -1418,10 +1386,8 @@ map_switch_event(struct trace_switch_event *switch_event,
 		die("hm, delta: %Ld < 0 ?\n", delta);
 
 
-	sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
-					      switch_event);
-	sched_in = threads__findnew_from_ctx(switch_event->next_pid,
-					     switch_event);
+	sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
+	sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
 
 	curr_thread[this_cpu] = sched_in;