Add experimental support for -j jobs building in the build

target.

MAKE_JOBS is undefined by default. You can test this by setting
in mk.conf: MAKE_JOBS=5 for example.

Some package just won't build correctly with this -- these individual
packages can set MAKE_JOBS_SAFE=no to disable it.

This is based on discussion from last December 2005. Some pkgsrc
users are using ideas like this.

Note I have been using this since December 2005 on various single
processor and multiprocessor systems. (Once I kept some stats on
performance but have misplaced that now.) I haved tested this with
many packages (but not a bulk build) on Linux, NetBSD and DragonFly.

This commit doesn't include the commits for the MAKE_JOB_SAFE. As
this is experimental it needs more testing. Some examples of problems
are: comms/lrzsz, databases/gramps2, editors/vim, graphics/MesaLib,
graphics/netpbm, net/bind9, print/ghostscript-esp, textproc/libxml,
and www/lynx.

2 files changed, 18 insertions, 4 deletions

diff --git a/mk/build/build.mk b/mk/build/build.mk
index 4bdb931f579..c16acd23eec 100644
--- a/mk/build/build.mk
+++ b/mk/build/build.mk
@@ -1,4 +1,4 @@
-# $NetBSD: build.mk,v 1.6 2006/09/09 02:35:13 obache Exp $
+# $NetBSD: build.mk,v 1.7 2006/10/05 23:35:23 reed Exp $
 #
 # BUILD_MAKE_FLAGS is the list of arguments that is passed to the make
 #	process.
@@ -9,6 +9,12 @@
 BUILD_MAKE_FLAGS?=	${MAKE_FLAGS}
 BUILD_TARGET?=		all
 
+.if defined(MAKE_JOBS_SAFE) && !empty(MAKE_JOBS_SAFE:M[nN][oO])
+_MAKE_JOBS=	# nothing
+.elif defined(MAKE_JOBS)
+_MAKE_JOBS=	-j${MAKE_JOBS}
+.endif
+
 ######################################################################
 ### build (PUBLIC)
 ######################################################################
@@ -96,8 +102,8 @@ do-build:
 .  for _dir_ in ${BUILD_DIRS}
 	${_PKG_SILENT}${_PKG_DEBUG}${_ULIMIT_CMD}			\
 	cd ${WRKSRC} && cd ${_dir_} &&					\
-	${SETENV} ${MAKE_ENV} ${MAKE_PROGRAM} ${BUILD_MAKE_FLAGS}	\
-		-f ${MAKE_FILE} ${BUILD_TARGET}
+	${SETENV} ${MAKE_ENV} ${MAKE_PROGRAM} ${_MAKE_JOBS} 		\
+		${BUILD_MAKE_FLAGS} -f ${MAKE_FILE} ${BUILD_TARGET}
 .  endfor
 .endif
 
diff --git a/mk/defaults/mk.conf b/mk/defaults/mk.conf
index ebe7a1b0c53..68cd076ee5a 100644
--- a/mk/defaults/mk.conf
+++ b/mk/defaults/mk.conf
@@ -1,4 +1,4 @@
-# $NetBSD: mk.conf,v 1.131 2006/09/27 15:18:15 joerg Exp $
+# $NetBSD: mk.conf,v 1.132 2006/10/05 23:35:23 reed Exp $
 #
 
 # This file provides default values for variables that may be overridden
@@ -36,6 +36,14 @@ GZIP?=	-9
 # Possible: -[0-9], --fast, --best (see gzip(1))
 # Default: -9
 
+#MAKE_JOBS=	3
+# Set to maximum number of jobs ("make -j") for make to run at one time.
+# Possible: a positive integer (e.g. 17)
+# Default: not defined
+# Note that this is in testing. Some packages will not build with this.
+# Disabling this for an individual package can be done by setting
+# MAKE_JOBS_SAFE=NO within the per package Makefile.
+
 #MKCRYPTO= no
 # If not YES or yes, don't fetch, build or install crypto packages.
 # Possible: not defined, no