Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

[Glenn Morris]

Hi,


Alan Mackenzie wrote:

> --- a/lisp/emacs-lisp/bytecomp.el
> +++ b/lisp/emacs-lisp/bytecomp.el
> @@ -124,6 +124,7 @@
>  (require 'backquote)
>  (require 'macroexp)
>  (require 'cconv)
> +(require 'compile)

I would expect this extra require to slow down bootstrap, for an issue
that is not relevant to bootstrap (bug#33475)? Can this be avoided?

Indeed, my automatic overnight build today was about 13 mins, whereas
every previous day this month was < 11.5 mins.

Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

[Alan Mackenzie]

Hello, Glenn.

On Wed, Nov 28, 2018 at 11:37:55 -0500, Glenn Morris wrote:

> Hi,


> Alan Mackenzie wrote:

> > --- a/lisp/emacs-lisp/bytecomp.el
> > +++ b/lisp/emacs-lisp/bytecomp.el
> > @@ -124,6 +124,7 @@
> >  (require 'backquote)
> >  (require 'macroexp)
> >  (require 'cconv)
> > +(require 'compile)

> I would expect this extra require to slow down bootstrap, for an issue
> that is not relevant to bootstrap (bug#33475)?

I've looked at this, and I don't think there would be other than a
microscopic slowdown.  The previous version of bytecomp.el used at least
one function in compile.el (namely compilation-mode), suggesting that
compile.elc? is already loaded when bytecomp starts.  However, for some
fiddly reason a macro in compile.el was no longer defined, hence the
require.

> Can this be avoided?

Yes it can, by moving the declaration of emacs-lisp-compilation-mode
out of bytecomp.el, probably into compile.el itself.

> Indeed, my automatic overnight build today was about 13 mins, whereas
> every previous day this month was < 11.5 mins.

I've timed several builds, and seen no differences between before and
after, appart from normal measurement error.  I see 2min 29sec +- 1
second for "cold starts", and 2min 3sec += 1 second for a subsequent
build, when all the source files are in filestore cache.

Are you sure that bug #33475 is the cause of your slowdown?

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

[Glenn Morris]

Alan Mackenzie wrote:

> The previous version of bytecomp.el used at least one function in
> compile.el (namely compilation-mode), suggesting that compile.elc? is
> already loaded when bytecomp starts.

It only uses compilation-mode in interactive use, but 1ca436a33c loads
compile unconditionally.

> However, for some fiddly reason a macro in compile.el was no longer
> defined, hence the require.

Since AFAICS you only need the define-compilation-mode macro,
eval-when-compile should solve the slowdown.

Re: master 1ca436a: Make compilation mode work with warnings from compiled buffer functions

[Alan Mackenzie]

Hello, Glenn.

On Wed, Nov 28, 2018 at 22:51:02 -0500, Glenn Morris wrote:
> Alan Mackenzie wrote:

> > The previous version of bytecomp.el used at least one function in
> > compile.el (namely compilation-mode), suggesting that compile.elc? is
> > already loaded when bytecomp starts.

> It only uses compilation-mode in interactive use, but 1ca436a33c loads
> compile unconditionally.

> > However, for some fiddly reason a macro in compile.el was no longer
> > defined, hence the require.

> Since AFAICS you only need the define-compilation-mode macro,
> eval-when-compile should solve the slowdown.

Ah, I've got you now!  Yes, that does indeed save a few seconds on the
bootstrap time.  Thanks for making the change in the repository.

-- 
Alan Mackenzie (Nuremberg, Germany).