Re: Time to merge scratch/correct-warning-pos into master, perhaps?

[Gregory Heytings]

> I've just tried timing $ make -j17 check on an up to date master, and a 
> master two - four weeks old, both configured the same, with native 
> compilation.  Much of the run time was taken by native compilation.
>
> The two times were 42.966s and 48.547s.  That's a difference of just 
> under 13%.  Not a systematic comparison, since make check may have got 
> bigger in the last few weeks.

Which is consistent with the results I reported: about 40% of the time of 
make check is used for byte-compilation, which is slowed down by ~17.5%, 
and the rest is execution, which is slowed down by ~11%.

> I don't think Gregory has ever been specific about what precisely he has 
> timed, and how.

Of course I have.  I timed make check, which everyone can do, and which 
you just did.

> There is no "all" in the 10% slow down.  That is a measure of the 
> slowdown of $ make check, nothing else.

It's the time to execute ~110K lines of Elisp, exercising various parts of 
Emacs.  It's IMO a much more significant number than an ad-hoc 
micro-benchmark.  It's perhaps not the only one to take into account, but 
it cannot be ignored either.

> But nobody else cared enough about the boostrap time to bother putting 
> in the use of the byte-compiled compiler in early bootstrap until I did 
> a week or so ago.

You may have seen that this optimization has no effect without 
--with-native-compilation.  This may explain that.