re: Parallel build failure on OSX

[matthew green <mrg%eterna.com.au@localhost>]

Joerg Sonnenberger writes:
> On Tue, Jan 13, 2015 at 05:26:21AM +1100, matthew green wrote:
> > 
> > > > Any way line 98 of version 1.49 src/share/mk/bsd.obj.mk has a mkdir 
> > > > without -p and I expect thatâ??s whatâ??s causing the immediate problem.
> > > So is it consensus that the -p ought to be added there?
> > > It looks very reasonable to me and it also looks very reasonable that it's 
> > > hard to run into the problem not only because it's a race, but also because 
> > > you have to start with something like a fresh CVS checkout to make it happen.
> > 
> > i don't think it's resaonable because it is pointing out a real
> > issue.  what could happen is that two "dependall" phases could
> > enter at the same time and stomp on each other, and the "-p" fix
> > will paper over one symptom of the real problem (the one that
> > actually catches stuff, it seems, since this is a long standing
> > problem that appears to exist in multiple places.)
> 
> Not really, dependall will have been executed for the do-lib phase
> already, so the (second) call in do-build does nothing.

OK, it avoids it for the do-build target, but not for anything
else, including all the targets run in a build (like obj or
includes.)

it's one thing to traverse multiple times serially, but this is
happening in parallel.  that can't be a good thing.


.mrg.