Re: cost of -MP

[Noel Yap]

Sorry for the confusion and for inadvertently implying you were stupid.  In one 
of your previous posts, you had said:

> It is 19 make re-executions. The reason non-recursive is slower is that I
> haven't had a chance to optimize it yet. I actually expect it to be faster
> than recursive (for obvious reasons).

I hope you can understand where my confusion lies.

To help my understanding, would you mind answering the following questions, 
please?

Currently, are the dependencies files regenerated due to a "-include", or as 
part of the object file being built?

When you say "re-exec", do you mean a re-exec due to an included makefile being 
rebuilt?  Or due to make recursively calling itself?

Can you elaborate on what you mean by "up-to-date build" below?

Thanks,
Noel

Boris Kolpackov wrote:

> Noel Yap <address@hidden> writes:
>
> > It just occurred to me:
> >
> > If the re-exec's are occurring due to the dependencies file generation, 
> > then converting to the more advanced way of generating dependencies files 
> > will eliminate the 19 re-exec's.
>
> Noel, I am not that stupid ;-). I run tests on an up-to-date build and
> all those 19 re-execs are because of the recursive structure.
>
> > So, try to optimize away the re-exec's first 
>
> I already did, in my non-recursive build ;-)