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From: mark@deltam.com (mark galbraith)
Newsgroups: gnu.utils.bug
Subject: Bug in GNU Make
Message-ID: <9001180502.AA00631@flyer.deltam.com>
Date: 18 Jan 90 05:02:17 GMT
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 31

When using the -j command line option on a target with many dependancies (e.g.,
linking several .o files into a single executable), make is not waiting for the
jobs building the dependacy files to finish before attempting to start the final
target build.

In example, consider the following entry in a Makefile:

	prog:	modulea.o moduleb.o modulec.o

Even by using the default rules for everything, if you start make with the -j
option set to 4, make will start the three compiles for modulea, moduleb, and
modulec; and then, without waiting for those jobs to finish, will also start
the link of prog.

What I would have expected to occur is that the make checks to see if a job is
dependant on one or more jobs still running.  If so, skip this job for now, leaving
it at the top of the list of jobs that must be done, and start the next job on
the job list.  Each time a job finishes, check from the top of the list down to
find the first job that can be run, that doesn't depend on a job that is currently
running.  If no job can be found, sleep until the next job terminates.  Eventually
all of the dependancy jobs will finish for the target, and the dependant job will
be run.

What I am asking for may be too much to ask (I haven't had much of a chance to
look into the code that handles jobs), but I would be interested in devoting what
time I have in fixing this problem.  I can't guarantee much, but what is available
will have to do.  Let me know if you would like me to pursue this bug.
--
Mark Galbraith				Voice:  415-449-6881
Programmer/Postmaster			UUCP:   uunet!deltam!mark
System Administrator			Domain: mark@deltam.com