RE: Parallel builds and SUBDIRS

[Dan Kegel <dkegel at ixiacom dot com>]

The Right Way to do this is to include all the
subdir makefile fragments into one big happy
make; then no special locking is needed.
(A la "recursive make considered harmful".)

Boy, that's a big change, though.
- Dan

-----Original Message-----
From: Harlan Stenn
To: automake@gnu.org
Sent: 5/17/2002 5:41 PM
Subject: Parallel builds and SUBDIRS

First, I'm not saying this is a good idea.

I'm working on a project where Somebody decided it would be a feature to
hack the automake templates to permit subdirs to be built in parallel.

They implemented an additional level of locking to prevent, for example,
a
library that is needed by multiple subdirs from being built
simultaneously.

I'm wondering if there is benefit to allowing SUBDIRS to be build in
parallel by option (or default), and wondering if it's possible,
reasonable,
and not too difficult to use dependency lines in the "parent"
Makefile.am to
control serialization, ie:

 SUBDIRS = include lib bar baz foo

 lib: include
 bar baz foo: lib

so that in a parallel build situation, we'd build include first, then
lib,
then bar, baz and foo in parallel.

Comments?

H