[tip:perf/urgent] perf sched timehist: Show callchains for idle stat

tip-bot for Namhyung Kim
2016-12-20T19:22:48Z

Commit-ID: ba957ebb54893acaf3dc846031073a63f021cee1
Gitweb: http://git.kernel.org/tip/ba957ebb54893acaf3dc846031073a63f021cee1
Author: Namhyung Kim <namhyung@kernel.org>
AuthorDate: Thu, 8 Dec 2016 23:47:55 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 15 Dec 2016 16:25:45 -0300

perf sched timehist: Show callchains for idle stat

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
...

Committer notes:

Extra testing:

# uname -a
Linux jouet 4.8.8-300.fc25.x86_64 #1 SMP Tue Nov 15 18:10:06 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

1) Run 'perf sched record -g'

2) Run 'perf sched timehist --idle --summary'

<SNIP>
Idle stats by callchain:
CPU 0: 13456.840 msec
Idle time (msec) Count Callchains
---------------- ----- --------------------------------------------------
5386.637 3283 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
2750.238 2299 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- do_syscall_64
1275.672 1287 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- entry_SYSCALL_64_fastpath
936.322 452 worker_thread <- kthread <- ret_from_fork
741.311 385 rcu_nocb_kthread <- kthread <- ret_from_fork
729.385 248 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_ppoll
365.386 229 irq_thread <- kthread <- ret_from_fork
338.934 265 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- entry_SYSCALL_64_fastpath
219.488 201 schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
186.839 410 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- do_syscall_64
142.541 59 kvm_vcpu_block <- kvm_arch_vcpu_ioctl_run <- kvm_vcpu_ioctl <- do_vfs_ioctl <- sys_ioctl
83.887 92 smpboot_thread_fn <- kthread <- ret_from_fork
62.722 96 do_exit <- do_group_exit <- 0x2a5594 <- entry_SYSCALL_64_fastpath
47.894 83 pipe_wait <- pipe_read <- __vfs_read <- vfs_read <- sys_read
46.554 61 rcu_gp_kthread <- kthread <- ret_from_fork
34.337 21 schedule_timeout <- intel_fbc_work_fn <- process_one_work <- worker_thread <- kthread
29.521 14 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_select <- core_sys_select
20.274 10 schedule_timeout <- io_schedule_timeout <- bit_wait_io <- __wait_on_bit <- out_of_line_wait_on_bit
15.085 55 schedule_timeout <- unix_stream_read_generic <- unix_stream_recvmsg <- sock_recvmsg <- SYSC_recvfrom
<SNIP>

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-7-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
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 0b14265..c1c07bf 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2448,6 +2448,9 @@ static int timehist_sched_change_event(struct perf_tool *tool,
last_tr->dt_wait = 0;
last_tr->dt_delay = 0;

+ if (itr->cursor.nr)
+ callchain_append(&itr->callchain, &itr->cursor, t - tprev);
+
itr->last_thread = NULL;
}
}
@@ -2557,6 +2560,60 @@ 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)
{
@@ -2615,6 +2672,35 @@ 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"