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Commit 97ea1a7fa62af0d8d49a0fc12796b0073537c9d8

Authored by Frederic Weisbecker
Committed by Ingo Molnar
1 parent 2e538c4a18
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 3 changed files with 13 additions and 68 deletions Side-by-side Diff

tools/perf/builtin-sched.c
Diff comments   View file @ 97ea1a7
... ... @@ -638,7 +638,7 @@
638 638 {
639 639 struct thread *thread;
640 640  
641   - thread = threads__findnew(event->comm.pid, &threads, &last_match);
  641 + thread = threads__findnew(event->comm.tid, &threads, &last_match);
642 642  
643 643 dump_printf("%p [%p]: perf_event_comm: %s:%d\n",
644 644 (void *)(offset + head),
... ... @@ -1034,36 +1034,6 @@
1034 1034 atoms->nb_atoms++;
1035 1035 }
1036 1036  
1037   -static struct thread *
1038   -threads__findnew_from_ctx(u32 pid, struct trace_switch_event *switch_event)
1039   -{
1040   - struct thread *th;
1041   -
1042   - th = threads__findnew_nocomm(pid, &threads, &last_match);
1043   - if (th->comm)
1044   - return th;
1045   -
1046   - if (pid == switch_event->prev_pid)
1047   - thread__set_comm(th, switch_event->prev_comm);
1048   - else
1049   - thread__set_comm(th, switch_event->next_comm);
1050   - return th;
1051   -}
1052   -
1053   -static struct thread *
1054   -threads__findnew_from_wakeup(struct trace_wakeup_event *wakeup_event)
1055   -{
1056   - struct thread *th;
1057   -
1058   - th = threads__findnew_nocomm(wakeup_event->pid, &threads, &last_match);
1059   - if (th->comm)
1060   - return th;
1061   -
1062   - thread__set_comm(th, wakeup_event->comm);
1063   -
1064   - return th;
1065   -}
1066   -
1067 1037 static void
1068 1038 latency_switch_event(struct trace_switch_event *switch_event,
1069 1039 struct event *event __used,
... ... @@ -1089,10 +1059,8 @@
1089 1059 die("hm, delta: %Ld < 0 ?\n", delta);
1090 1060  
1091 1061  
1092   - sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
1093   - switch_event);
1094   - sched_in = threads__findnew_from_ctx(switch_event->next_pid,
1095   - switch_event);
  1062 + sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
  1063 + sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
1096 1064  
1097 1065 out_events = thread_atoms_search(&atom_root, sched_out, &cmp_pid);
1098 1066 if (!out_events) {
... ... @@ -1158,7 +1126,7 @@
1158 1126 if (!wakeup_event->success)
1159 1127 return;
1160 1128  
1161   - wakee = threads__findnew_from_wakeup(wakeup_event);
  1129 + wakee = threads__findnew(wakeup_event->pid, &threads, &last_match);
1162 1130 atoms = thread_atoms_search(&atom_root, wakee, &cmp_pid);
1163 1131 if (!atoms) {
1164 1132 thread_atoms_insert(wakee);
... ... @@ -1418,10 +1386,8 @@
1418 1386 die("hm, delta: %Ld < 0 ?\n", delta);
1419 1387  
1420 1388  
1421   - sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
1422   - switch_event);
1423   - sched_in = threads__findnew_from_ctx(switch_event->next_pid,
1424   - switch_event);
  1389 + sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
  1390 + sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
1425 1391  
1426 1392 curr_thread[this_cpu] = sched_in;
1427 1393  
tools/perf/util/thread.c
Diff comments   View file @ 97ea1a7
... ... @@ -6,17 +6,15 @@
6 6 #include "util.h"
7 7 #include "debug.h"
8 8  
9   -static struct thread *thread__new(pid_t pid, int set_comm)
  9 +static struct thread *thread__new(pid_t pid)
10 10 {
11 11 struct thread *self = calloc(1, sizeof(*self));
12 12  
13 13 if (self != NULL) {
14 14 self->pid = pid;
15   - if (set_comm) {
16   - self->comm = malloc(32);
17   - if (self->comm)
18   - snprintf(self->comm, 32, ":%d", self->pid);
19   - }
  15 + self->comm = malloc(32);
  16 + if (self->comm)
  17 + snprintf(self->comm, 32, ":%d", self->pid);
20 18 self->maps = RB_ROOT;
21 19 INIT_LIST_HEAD(&self->removed_maps);
22 20 }
... ... @@ -52,10 +50,8 @@
52 50 return ret;
53 51 }
54 52  
55   -static struct thread *
56   -__threads__findnew(pid_t pid, struct rb_root *threads,
57   - struct thread **last_match,
58   - int set_comm)
  53 +struct thread *
  54 +threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
59 55 {
60 56 struct rb_node **p = &threads->rb_node;
61 57 struct rb_node *parent = NULL;
... ... @@ -84,8 +80,7 @@
84 80 p = &(*p)->rb_right;
85 81 }
86 82  
87   - th = thread__new(pid, set_comm);
88   -
  83 + th = thread__new(pid);
89 84 if (th != NULL) {
90 85 rb_link_node(&th->rb_node, parent, p);
91 86 rb_insert_color(&th->rb_node, threads);
... ... @@ -93,19 +88,6 @@
93 88 }
94 89  
95 90 return th;
96   -}
97   -
98   -struct thread *
99   -threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
100   -{
101   - return __threads__findnew(pid, threads, last_match, 1);
102   -}
103   -
104   -struct thread *
105   -threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
106   - struct thread **last_match)
107   -{
108   - return __threads__findnew(pid, threads, last_match, 0);
109 91 }
110 92  
111 93 struct thread *
tools/perf/util/thread.h
Diff comments   View file @ 97ea1a7
... ... @@ -18,9 +18,6 @@
18 18 struct thread *
19 19 threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match);
20 20 struct thread *
21   -threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
22   - struct thread **last_match);
23   -struct thread *
24 21 register_idle_thread(struct rb_root *threads, struct thread **last_match);
25 22 void thread__insert_map(struct thread *self, struct map *map);
26 23 int thread__fork(struct thread *self, struct thread *parent);