Re: [PATCH 2/2] time: alarmtimer: Add the trcepoints for alarmtimer

From: Steven Rostedt
Date: Wed Sep 21 2016 - 09:33:56 EST

On Wed, 21 Sep 2016 14:36:23 +0200 (CEST)
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> On Wed, 21 Sep 2016, Steven Rostedt wrote:
> > On Wed, 21 Sep 2016 09:26:20 +0200 (CEST)
> > Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > > A single u64 does not take more storage space than this and it's a single
> > > store.
> >
> > So to use rtc_tm_to_time64()? Is the work to do the calculations of the
> > conversion faster than a bunch of stores that are going to be in hot
> > cache?
> Look at the call site. It has already the scalar nsec value and it does a
> conversion to rtc time in order to trace it.

OK. I haven't looked at the callsite. I just did a quick look at the
patch as is, and noticed the wasted space in the buffer for storing a
bunch of ints that will never be bigger than 256.

> Ditto for the other tracepoints where the conversion from scalar nsec is
> done in the tracepoint itself.

This is why I like to have the maintainers review the rest.

-- Steve