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Subject[tip:perf/core] perf tools: Improve thread comm resolution in perf sched
Commit-ID:  9a92b479b2f088ee2d3194243f4c8e59b1b8c9c2
Gitweb: http://git.kernel.org/tip/9a92b479b2f088ee2d3194243f4c8e59b1b8c9c2
Author: Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Thu, 8 Oct 2009 16:37:12 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 8 Oct 2009 16:56:33 +0200

perf tools: Improve thread comm resolution in perf sched

When we get sched traces that involve a task that was already
created before opening the event, we won't have the comm event for
it.

So if we can't find the comm event for a given thread, we look at
the traces that may contain these informations.

Before:

ata/1:371 | 0.000 ms | 1 | avg: 3988.693 ms | max: 3988.693 ms |
kondemand/1:421 | 0.096 ms | 3 | avg: 345.346 ms | max: 1035.989 ms |
kondemand/0:420 | 0.025 ms | 3 | avg: 421.332 ms | max: 964.014 ms |
:5124:5124 | 0.103 ms | 5 | avg: 74.082 ms | max: 277.194 ms |
:6244:6244 | 0.691 ms | 9 | avg: 125.655 ms | max: 271.306 ms |
firefox:5080 | 0.924 ms | 5 | avg: 53.833 ms | max: 257.828 ms |
npviewer.bin:6225 | 21.871 ms | 53 | avg: 22.462 ms | max: 220.835 ms |
:6245:6245 | 9.631 ms | 21 | avg: 41.864 ms | max: 213.349 ms |
After:

ata/1:371 | 0.000 ms | 1 | avg: 3988.693 ms | max: 3988.693 ms |
kondemand/1:421 | 0.096 ms | 3 | avg: 345.346 ms | max: 1035.989 ms |
kondemand/0:420 | 0.025 ms | 3 | avg: 421.332 ms | max: 964.014 ms |
firefox:5124 | 0.103 ms | 5 | avg: 74.082 ms | max: 277.194 ms |
npviewer.bin:6244 | 0.691 ms | 9 | avg: 125.655 ms | max: 271.306 ms |
firefox:5080 | 0.924 ms | 5 | avg: 53.833 ms | max: 257.828 ms |
npviewer.bin:6225 | 21.871 ms | 53 | avg: 22.462 ms | max: 220.835 ms |
npviewer.bin:6245 | 9.631 ms | 21 | avg: 41.864 ms | max: 213.349 ms |
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: <1255012632-7882-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
tools/perf/builtin-sched.c | 44 +++++++++++++++++++++++++++++++++++++++-----
tools/perf/util/thread.c | 32 +++++++++++++++++++++++++-------
tools/perf/util/thread.h | 3 +++
3 files changed, 67 insertions(+), 12 deletions(-)
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index e1df705..25b91e7 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1034,6 +1034,36 @@ 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,
@@ -1059,8 +1089,10 @@ latency_switch_event(struct trace_switch_event *switch_event,
die("hm, delta: %Ld < 0 ?\n", delta);


- sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
- sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
+ sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
+ switch_event);
+ sched_in = threads__findnew_from_ctx(switch_event->next_pid,
+ switch_event);

out_events = thread_atoms_search(&atom_root, sched_out, &cmp_pid);
if (!out_events) {
@@ -1126,7 +1158,7 @@ latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
if (!wakeup_event->success)
return;

- wakee = threads__findnew(wakeup_event->pid, &threads, &last_match);
+ wakee = threads__findnew_from_wakeup(wakeup_event);
atoms = thread_atoms_search(&atom_root, wakee, &cmp_pid);
if (!atoms) {
thread_atoms_insert(wakee);
@@ -1386,8 +1418,10 @@ map_switch_event(struct trace_switch_event *switch_event,
die("hm, delta: %Ld < 0 ?\n", delta);


- sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
- sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
+ sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
+ switch_event);
+ sched_in = threads__findnew_from_ctx(switch_event->next_pid,
+ switch_event);

curr_thread[this_cpu] = sched_in;

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 3b56aeb..8bd5ca2 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -6,15 +6,17 @@
#include "util.h"
#include "debug.h"

-static struct thread *thread__new(pid_t pid)
+static struct thread *thread__new(pid_t pid, int set_comm)
{
struct thread *self = calloc(1, sizeof(*self));

if (self != NULL) {
self->pid = pid;
- self->comm = malloc(32);
- if (self->comm)
- snprintf(self->comm, 32, ":%d", self->pid);
+ if (set_comm) {
+ self->comm = malloc(32);
+ if (self->comm)
+ snprintf(self->comm, 32, ":%d", self->pid);
+ }
self->maps = RB_ROOT;
INIT_LIST_HEAD(&self->removed_maps);
}
@@ -50,8 +52,10 @@ static size_t thread__fprintf(struct thread *self, FILE *fp)
return ret;
}

-struct thread *
-threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
+static struct thread *
+__threads__findnew(pid_t pid, struct rb_root *threads,
+ struct thread **last_match,
+ int set_comm)
{
struct rb_node **p = &threads->rb_node;
struct rb_node *parent = NULL;
@@ -80,7 +84,8 @@ threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
p = &(*p)->rb_right;
}

- th = thread__new(pid);
+ th = thread__new(pid, set_comm);
+
if (th != NULL) {
rb_link_node(&th->rb_node, parent, p);
rb_insert_color(&th->rb_node, threads);
@@ -91,6 +96,19 @@ threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
}

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 845d9b6..75bc843 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -18,6 +18,9 @@ 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);

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