Re: perf,tools: Remove usage of trace_sched_wakeup(.success)

[Peter Zijlstra]

On Tue, May 13, 2014 at 03:34:32PM +0900, Dongsheng Yang wrote:
> On 05/13/2014 04:22 PM, Ingo Molnar wrote:
> >* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> >>trace_sched_wakeup(.success) is a dead argument and has been for ages,
> >Always 0, or random value?
> 
> Hi Ingo,
> 
> It is always 1 currently.
> 
> Peter believe that .success is not useful and I pointed that perf sched
> latency
> is using it now. Then he post this patch to remove the usage here.
> 
> Please go to the following link for more about this issue.

It is _not_ usable. You're proposing to abuse the existing parameter. A
wakeup doing an enqueue or not has nothing _WHAT_SO_EVER_ to do with
success.

Now what I think you wanted to do is make it easier to match
trace_sched_switch() statements with trace_sched_wakeup() statements.
And since you only get the trace_sched_switch() on dequeue, you want to
know which trace_sched_wakeup() calls did an enqueue.

But that's completely and utterly unrelated to success.

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