[PATCH v2 6/6] perf sched timehist: Show callchains for idle stat

Namhyung Kim
2016-12-08T14:49:37Z

When --idle-hist option is used with --summary, it now shows idle stats
with callchains like below:

Idle stats by callchain:
CPU 0: 902.195 msec
Idle time (msec) Count Callchains
---------------- -------- --------------------------------------------------
370.589 69 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- entry_SYSCALL_64_fastpath
178.799 17 worker_thread <- kthread <- ret_from_fork
128.352 17 schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
125.111 19 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_select <- core_sys_select
71.599 50 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
23.146 1 rcu_gp_kthread <- kthread <- ret_from_fork
4.510 1 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- do_syscall_64
0.085 1 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- do_restart_poll
...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/builtin-sched.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 6dc9e00d6392..724134203632 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2438,6 +2438,9 @@ static int timehist_sched_change_event(struct perf_tool *tool,
goto out;

timehist_update_runtime_stats(last_tr, t, tprev);
+ if (itr->cursor.nr)
+ callchain_append(&itr->callchain, &itr->cursor,
+ t - tprev);

itr->last_thread = NULL;
}
@@ -2548,6 +2551,60 @@ static int show_deadthread_runtime(struct thread *t, void *priv)
return __show_thread_runtime(t, priv);
}

+static size_t callchain__fprintf_folded(FILE *fp, struct callchain_node *node)
+{
+ const char *sep = " <- ";
+ struct callchain_list *chain;
+ size_t ret = 0;
+ char bf[1024];
+ bool first;
+
+ if (node == NULL)
+ return 0;
+
+ ret = callchain__fprintf_folded(fp, node->parent);
+ first = (ret == 0);
+
+ list_for_each_entry(chain, &node->val, list) {
+ if (chain->ip >= PERF_CONTEXT_MAX)
+ continue;
+ if (chain->ms.sym && chain->ms.sym->ignore)
+ continue;
+ ret += fprintf(fp, "%s%s", first ? "" : sep,
+ callchain_list__sym_name(chain, bf, sizeof(bf),
+ false));
+ first = false;
+ }
+
+ return ret;
+}
+
+static size_t timehist_print_idlehist_callchain(struct rb_root *root)
+{
+ size_t ret = 0;
+ FILE *fp = stdout;
+ struct callchain_node *chain;
+ struct rb_node *rb_node = rb_first(root);
+
+ printf(" %16s %8s %s\n", "Idle time (msec)", "Count", "Callchains");
+ printf(" %.16s %.8s %.50s\n", graph_dotted_line, graph_dotted_line,
+ graph_dotted_line);
+
+ while (rb_node) {
+ chain = rb_entry(rb_node, struct callchain_node, rb_node);
+ rb_node = rb_next(rb_node);
+
+ ret += fprintf(fp, " ");
+ print_sched_time(chain->hit, 12);
+ ret += 16; /* print_sched_time returns 2nd arg + 4 */
+ ret += fprintf(fp, " %8d ", chain->count);
+ ret += callchain__fprintf_folded(fp, chain);
+ ret += fprintf(fp, "\n");
+ }
+
+ return ret;
+}
+
static void timehist_print_summary(struct perf_sched *sched,
struct perf_session *session)
{
@@ -2606,6 +2663,35 @@ static void timehist_print_summary(struct perf_sched *sched,
printf(" CPU %2d idle entire time window\n", i);
}

+ if (sched->idle_hist && symbol_conf.use_callchain) {
+ callchain_param.mode = CHAIN_FOLDED;
+ callchain_param.value = CCVAL_PERIOD;
+
+ callchain_register_param(&callchain_param);
+
+ printf("\nIdle stats by callchain:\n");
+ for (i = 0; i < idle_max_cpu; ++i) {
+ struct idle_thread_runtime *itr;
+
+ t = idle_threads[i];
+ if (!t)
+ continue;
+
+ itr = thread__priv(t);
+ if (itr == NULL)
+ continue;
+
+ callchain_param.sort(&itr->sorted_root, &itr->callchain,
+ 0, &callchain_param);
+
+ printf(" CPU %2d:", i);
+ print_sched_time(itr->tr.total_run_time, 6);
+ printf(" msec\n");
+ timehist_print_idlehist_callchain(&itr->sorted_root);
+ printf("\n");
+ }
+ }
+
printf("\n"
" Total number of unique tasks: %" PRIu64 "\n"
"Total number of context switches: %" PRIu64 "\n"
--
2.10.1