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perf tools: Improve thread comm resolution in perf sched
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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>
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Frederic Weisbecker authored and Ingo Molnar committed Oct 8, 2009
1 parent 016e92f commit 9a92b47
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Showing 3 changed files with 67 additions and 12 deletions.
44 changes: 39 additions & 5 deletions tools/perf/builtin-sched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;

Expand Down
32 changes: 25 additions & 7 deletions tools/perf/util/thread.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -90,6 +95,19 @@ threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
return th;
}

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)
{
Expand Down
3 changes: 3 additions & 0 deletions tools/perf/util/thread.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down

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