Re: is anyone using threaded automake?

[Jason Sewall]

On Sun, Nov 1, 2009 at 6:45 AM, Ralf Wildenhues <address@hidden> wrote:
> Since the 1.11 release I have not seen one bug report about
> $AUTOMAKE_JOBS aka. automake running several Perl threads to
> update several Makefile.in files concurrently, for speed.
> If you have more than a couple of Makefile.am files and a SMP
> system, then it should help.
>
> Is anyone using it?  Has anyone seen issues with it?

I didn't even know it existed, but I just tried it out and it seems to
generate correct output for a project I have with 12 Makefile.am
files. I have a quad core machine and set AUTOMAKE_JOBS=4.

The performance gains are fairly small, however:
$ AUTOMAKE_JOBS=1 time automake
1.31user 0.19system 0:01.51elapsed 100%CPU

$ AUTOMAKE_JOBS=4 time automake
1.62user 0.24system 0:01.14elapsed 163%CPU

And they are imperceptible with autoreconf.

> Bugs could manifest in unstable Makefile.in content,
> i.e., running it a second time creates a different file,
> and/or unstable warning/error output from automake, thus by
> definition be hard to detect and hard to debug.  Which is
> why I'm asking whether I should assume "it just works" or
> "nobody uses it" or "there is not enough use to expose bugs".

I made two copies of the project, ran AUTOMAKE_JOBS=1 autoreconf -i in
one and AUTOMAKE_JOBS=20 autoreconf -i in another and diff -r said the
results were the same.

FWIW,
Jason