Re: [bug #40639] GNU Make with profiling information

[Reinier Post]

On Wed Nov 20 22:47:20 2013, address@hidden (Eddy Petrișor) wrote:
> > On Tue Nov 19 22:29:22 2013, Reinier Post wrote:
> >> Follow-up Comment #1, bug #40639 (project make):
> >> 
> >> I have created a cleaned up rebased branch that contains only changes for 
> >> the
> >> profiling feature so it can be easier to review.
> >> 
> >> https://github.com/eddyp/make-profiler/tree/profile-rebase
> >> 
> >> Please note this branch will be rebased. Use 'git pull --rebase' if you 
> >> need
> >> to resync.
> > 
> > Looks very useful!
> > 
> > Can't this functionality be provided by a wrapper $SHELL?
> > Sure, it's an extra exec(),
> > but it will keep the make code base simpler.
> 
> I'm not sure if I understand what you mean. Do you mean wrapping all target 
> invokes in a $SHELL?

Yes; something line /usr/bin/time.

> If that's the case, you don't get the actual/real-time measurement, and that 
> might skew your profiling information.

True.  Hnow how much of a difference does it make?

> I have some build systems that can take easily over 12 hours to do a full 
> build (several thousands of elfs in recursive
> make calls - I know that's bad, I am working on it), so any extra time waste 
> just for the measurement can mean
> significant delays in getting the results.

If it's 15 minutes, they are not the thing you want to optimize first.
The build is probably running overnight anyway.

Can you measure it?

-- 
Reinier Post
TU EIndhoven