Module Name:	basesrc
Committed By:	sommerfeld
Date:		Sat Dec 30 02:05:21 UTC 2000

Modified Files:
	basesrc/usr.bin/make: Makefile job.c job.h main.c make.1 make.c make.h

Log Message:
Add a token-passing scheme to allow a recursive make to successfully
use -j; all make's in a recursive build cooperate to limit the total
number of jobs, using a token-passing scheme.

The current token passing algorithm is similar to the one implemented
by gmake; there is a single pipe which is inherited through the entire
process hierarchy; tokens are obtained by reading a byte from the
"read end" of the pipe, and are returned by writing them to the "write
end".  This exact algorithm is likely to change in the future.

Implementation details:
 - Use the new trace facility to allow measurement of the
effectiveness of different token-passing schemes
 - Get a token in MakeStartJobs(), return it in Make_Update()
 - Eliminate Job_Full() and the jobFull global since they are
redundant with token system.
 - Add an "internal" -J option (to pass the token pipe fd's down to
submakes) and a -T option for tracing.
 - Change how compatMake is forced so that -j means something when
inherited by submakes.
 - When waiting for a token, poll the token-passing pipe as well as
the output pipes of existing jobs.


To generate a diff of this commit:
cvs rdiff -r1.21 -r1.22 basesrc/usr.bin/make/Makefile
cvs rdiff -r1.39 -r1.40 basesrc/usr.bin/make/job.c
cvs rdiff -r1.10 -r1.11 basesrc/usr.bin/make/job.h
cvs rdiff -r1.57 -r1.58 basesrc/usr.bin/make/main.c
cvs rdiff -r1.43 -r1.44 basesrc/usr.bin/make/make.1
cvs rdiff -r1.31 -r1.32 basesrc/usr.bin/make/make.c
cvs rdiff -r1.29 -r1.30 basesrc/usr.bin/make/make.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.