Messages in this thread | | | Date | Sun, 11 May 2014 14:52:24 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] sched: Distinguish sched_wakeup event when wake up a task which did schedule out or not. |
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On Sun, 11 May 2014 18:35:31 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> So if the wait side has already observed cond==false, then without the > wakeup, which still potentially has ->on_rq == true, it would block. > Therefore the wakeup is a _real_ wakeup. > > We fundamentally cannot know, on the wake side, if the wait side has or > has not observed cond, and therefore the distinction you're trying to > make is a false one.
I believe you may be misunderstanding Dongsheng. It has nothing to do with the wake condition. But the "success" is basically saying, "did I move the task on to the run queue?". That's a relevant piece of information that the wake up event isn't currently showing.
Let me ask you this; with Donsheng's patch, will there ever be a sched_switch event when the wakeup event sees 'false' and the sched_switch event see the task with a state other than "R"? And if so, how did the task doing the wakeup event, wake up that task?
-- Steve
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