From: Wilson Bilkovich <wilsonb@...>
Date: 2006-11-02T00:49:03+09:00
Subject: Re: parallel tasks with rake ?

On 11/1/06, quixoticsycophant@yahoo.com <quixoticsycophant@yahoo.com> wrote:
> I was excited to switch my makefile system to rake, but I just noticed
> rake lacks a (GNU) make option I can't live without: -j4.  It's like
> "make & ; make & ; make & ; make &" but with the parallel jobs
> properly synchronized.  On a quad-core machine this makes a world of
> difference, being around four times faster than a simple 'make'.
>
> As I understand it, rake should be able to determine which targets can
> be built in parallel just as (GNU) make does.  rake's multitask
> feature isn't quite right because it shouldn't be up to the user to
> determine parallel vs non-parallel tasks.  In fact, the user should
> probably never decide parallelism by fiat; even if the user happens to
> be correct, it creates a maintenance problem whereby additional tasks
> will eventually render the parallel assertion false.
>
> Perhaps there is something I'm missing about 'multitask' ?
>
>

How does Make figure out which jobs can be run in parallel? In my
experience, it just runs everything in parallel, and things break when
the tasks aren't safely parallelizable. (e.g. doing make -j4 install
on a FreeBSD port)