[lttng-dev] [RFC PATCH] sched: Fix sched_wakeup tracepoint

[xiyou.wangcong@gmail.com (Cong Wang)]

On Tue, Jun 9, 2015 at 2:13 AM, Peter Zijlstra <peterz at infradead.org> wrote:
>
> So how about we introduce the 'waking' tracepoint and leave the existing
> wakeup one in place and preserve its woken semantics.
>
> Steven, can we do aliases? Where one tracepoint is known to userspace
> under multiple names? In that case we could rename the thing to woken
> and have an alias wakeup which we can phase out over time.
>
> The patch also takes away the success parameter to the tracepoint, but
> does not quite go as far as actually removing it from the tracepoint
> itself.
>
> We can do that in a follow up patch which we can quickly revert if it
> turns out people are actually still using that for something.

+1 to this patch. How is it going?

Here at Twitter, we are analyzing scheduling latencies too, with our
own tool using existing tracepoints, it would be nice to have more
granularity on the scheduling latency.

And, you probably want to change perf sched to respect this
new 'waking' event too. ;)

Thanks.