cvs commit: src/usr.bin/make job.c job.h main.c make.c

[Poul-Henning Kamp]

Please see:

	http://phk.freebsd.dk/misc/make.png

It shows the loadaverage for "make -j 12 -s buildworld" with and without
this code.

Poul-Henning


In message <200411120858.iAC8w7ng088956 at repoman.freebsd.org>, Poul-Henning Kamp
 writes:
>phk         2004-11-12 08:58:07 UTC
>
>  FreeBSD src repository
>
>  Modified files:
>    usr.bin/make         job.c job.h main.c make.c 
>  Log:
>  Add code to enforce the paralleism count (-j N) for the entire tree
>  of submakes spawned during processing.
>  
>  We create a fifo and stuff one character into it for each job we are
>  allowed to run.  The name of the fifo is passed to child processes
>  in the MAKE_JOBS_FIFO environment variable.
>  
>  A make which finds this variable on startup will open the fifo and
>  only spawn jobs when it managed to read a token from the fifo.
>  When the job completes a token is writen back to the fifo.
>  
>  Slave make processes get one token for free: the one their parent
>  make got in order to run them.  This makes the make processes
>  themselves invisible in the process counts.
>  
>  The net effect is that "make -j 12 -s buildworld" will start at
>  most 12 jobs at the same time, instead of as previously up to
>  65 jobs would get started.
>  
>  Revision  Changes    Path
>  1.57      +114 -28   src/usr.bin/make/job.c
>  1.26      +1 -1      src/usr.bin/make/job.h
>  1.96      +2 -0      src/usr.bin/make/main.c
>  1.25      +2 -2      src/usr.bin/make/make.c
>

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.