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From: | Eddy Petrișor |
Subject: | Re: [bug #40639] GNU Make with profiling information |
Date: | Wed, 27 Nov 2013 09:56:55 +0200 |
Pe 25.11.2013 11:09, "Reinier Post" <address@hidden> a scris:
> > > 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.
Not on Windows.
> > 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?
Depends on how badly the build system is written. And that's what the target of the profiling is, finding out how bad is it. I feel that penalising the most exactly the build systems that need the least the slow down it's bad design.
> > 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.
If it's a live/production system, then any unknown slow down time might not be acceptable.
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