Re: [PATCH 10] PM: Measure suspend and resume times for individual devices (was: Re: [PATCH 2/6] PM: Asynchronous resume of devices)

Alan Stern
2009-08-31T14:09:55Z

On Sun, 30 Aug 2009, Rafael J. Wysocki wrote:

> > > For testing purposes it would be nice to have a one-line summary for
> > > each device containing a thread ID, start timestamp, end timestamp, and
> > > elapsed time. With that information you could evaluate the amount of
> > > parallelism and determine where the bottlenecks are. It would give a
> > > much more detailed picture of the entire process than the total time of
> > > your recent patch 9.
> >
> > Of course it would. I think I'll implement it.
>
> OK, below is a patch for that. It only prints the time elapsed, because the
> timestamps themselves can be obtained from the usual kernel timestamping.

Does that include the start timestamps? I don't see them anywhere in
the patch. Without the start timestamps we have no way to know how
much time was spent waiting for dpm_list_mtx or other resources as
opposed to actually carrying out the operation.

Alan Stern