From: quixoticsycophant@...
Date: 2006-11-02T04:15:17+09:00
Subject: Re: parallel tasks with rake ?


Hugh Sasse wrote:
> Would marking it as a .PHONY help?  I see little advice in the GNU
> make manual about how to get this sort of thing right for parallel
> make.  Where should one look for such info?

First of all, the workaround isn't so bad:

    $ make -j4 && make install

In order for 'make -j4 install' to work, the install target must
simply depend on everything it needs.  Needless to say, most Makefile
writers assume a 'make && make install' invocation and don't write
proper prerequisites for the install target.  In other words, they
assume a single-process make.

Marking the target .PHONY just means it will run unconditionally (so
for example Make won't be confused by a file named 'install') and
won't affect the correctness or incorrectness of the dependencies.

To get back to the original point, the dependency graph is what
decides parallelism, not the other way around.  Unless I misunderstand
the rake docs, the 'multitask' feature of rake is dangerous and should
be removed (see my original post).

Rake is a very nice tool, but it needs a -j equivalent in order to be
considered as an alternative to make (at least in my case).  I put it
out to enterprising rubyists to give rake genuine parallel task
execution.