Subject: Re: toolchain/21563: latest crunchgen break build.sh -j x for x >= 4
To: <>
From: David Laight <david@l8s.co.uk>
List: netbsd-bugs
Date: 05/15/2003 00:23:09
On Wed, May 14, 2003 at 10:37:37PM +0100, David Laight wrote:
> > 
> > That's strange a 'make -j 4 dependall' just after the build.sh failure
> > completed. but subsequent cleandir, make, make, ... fails over and over.
> 
> I may have a clue, 'nbmake -j 4 dependall' fails, but 'nbmake -j 4' works!
> So it must have something to do with precisely how 'dependall' is implemented.
> I'll have a look.

I have a horrid feeling that this is actually down to a bug in make itself!

Firstly, it isn't at all clear that '-j 1' has the desired effect.

However I've also discovered that parallel makes break some of the other
parts of the system.  Anything with:

x y: d
	cmd 

Will get 'cmd' running twice at the same time - which can, and does,
lead to corrupt files as well as wasted effort.
If 'cmd' creates both 'x' and 'y' it looks like you need:

x: y
	[ ! -f x ] || touch x
y: d
	cmd


	David

-- 
David Laight: david@l8s.co.uk