Re: [PATCH] perf sched: fix wrong conversion of task state

From: David Ahern
Date: Wed Jul 27 2016 - 12:50:35 EST


On 7/27/16 9:58 AM, 関山友輝 / SEKIYAMA,TOMOKI wrote:
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..eb2f7f4 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -71,6 +71,7 @@ struct sched_atom {
};

#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"
+#define TASK_STATE_MASK 0x7ff

The mask should not be needed and looking at top of tree there are 2 new
states (N and n) that need to be added.

I couldn't find the state for 'n'. Where can I find it?

Check Linus' tree -- top of tree; commit 7dc603c9028ea.


I have rechecked the code and found that __trace_sched_switch_state() uses
TASK_STATE_MAX for preempted tasks.

since TASK_STATE_MAX is kernel version dependent perf should not rely on it.

I will add 'N', and '+' (instead of "R+" ftrace shows) for preempted tasks.
(Also add_sched_out_event should set THREAD_WAIT_CPU for preempted tasks.)