On Thu, 2014-03-27 at 20:44 +0100, Dimitry Andric wrote:
> On 27 Mar 2014, at 19:12, Jilles Tjoelker <jil...@stack.nl> wrote:
> > On Thu, Mar 27, 2014 at 11:05:00AM -0600, Warner Losh wrote:
> >> On Mar 26, 2014, at 4:30 PM, Dimitry Andric <d...@freebsd.org> wrote:
> >>> Author: dim
> >>> Date: Wed Mar 26 22:30:38 2014
> >>> New Revision: 263778
> >>> URL: http://svnweb.freebsd.org/changeset/base/263778
> >
> >>> Log:
> >>> Add a SUBDIR_PARALLEL option to bsd.subdir.mk, to allow make to process
> >>> all the SUBDIR entries in parallel, instead of serially. Apply this
> >>> option to a selected number of Makefiles, which can greatly speed up the
> >>> build on multi-core machines, when using make -j.
> >
> >>> This can be extended to more Makefiles later on, whenever they are
> >>> verified to work correctly with parallel building.
> >
> >> Why not have this ‘opt out’ rather than ‘opt in’ like it is now? Are
> >> there any known bad dependencies this introduces?
> >
> > I'm paranoid about build systems ;) It is easy to add dependencies
> > across directories and as long as directories are built in sequence,
> > nothing goes wrong.
> >
> > In fact, I had enabled SUBDIR_PARALLEL in sys/modules/Makefile as well,
> > but this caused mysterious failures with some kernels such as mips
> > ADM5120.
>
> There are a bunch of other parts that don't really like parallel builds
> at the moment. For example, gnu/usr.bin/binutils needs its libraries
> (libbfd.a, etc) built first, before it can link the programs. Similar
> for gnu/usr.bin/cc, which needs libiberty, libcpp, etc before being able
> to build the rest of gcc.
>
> Most of these cases can hopefully be solved by adding .WAIT targets at
> strategic points in the SUBDIR lists, but this also needs a bit of extra
> logic in bsd.subdir.mk.
>
> -Dimitry
>
It turns out I needed the .WAIT functionality to use SUBDIR_PARALLEL for
$work, so I came up with the attached, does this look okay to commit?
-- Ian
diff -r 67802e319fc6 share/mk/bsd.subdir.mk
--- a/share/mk/bsd.subdir.mk Sun Apr 20 21:01:07 2014 -0600
+++ b/share/mk/bsd.subdir.mk Mon Apr 21 06:59:37 2014 -0600
@@ -4,10 +4,10 @@
# The include file <bsd.subdir.mk> contains the default targets
# for building subdirectories.
#
-# For all of the directories listed in the variable SUBDIRS, the
+# For all of the directories listed in the variable SUBDIR, the
# specified directory will be visited and the target made. There is
# also a default target which allows the command "make subdir" where
-# subdir is any directory listed in the variable SUBDIRS.
+# subdir is any directory listed in the variable SUBDIR.
#
#
# +++ variables +++
@@ -42,7 +42,7 @@ distribute:
_SUBDIR: .USE
.if defined(SUBDIR) && !empty(SUBDIR) && !defined(NO_SUBDIR)
- @${_+_}for entry in ${SUBDIR}; do \
+ @${_+_}for entry in ${SUBDIR:N.WAIT}; do \
if test -d ${.CURDIR}/$${entry}.${MACHINE_ARCH}; then \
${ECHODIR} "===> ${DIRPRFX}$${entry}.${MACHINE_ARCH} (${.TARGET:realinstall=install})"; \
edir=$${entry}.${MACHINE_ARCH}; \
@@ -57,7 +57,7 @@ distribute:
done
.endif
-${SUBDIR}: .PHONY
+${SUBDIR:N.WAIT}: .PHONY
${_+_}@if test -d ${.TARGET}.${MACHINE_ARCH}; then \
cd ${.CURDIR}/${.TARGET}.${MACHINE_ARCH}; \
else \
@@ -65,13 +65,18 @@ distribute:
fi; \
${MAKE} all
+__wait=.WAIT
.for __target in all all-man checkdpadd clean cleandepend cleandir \
depend distribute lint maninstall manlint \
obj objlink realinstall regress tags \
${SUBDIR_TARGETS}
.ifdef SUBDIR_PARALLEL
+__subdir_targets=
.for __dir in ${SUBDIR}
-${__target}: ${__target}_subdir_${__dir}
+.if ${__wait} == ${__dir}
+__subdir_targets+= .WAIT
+.else
+__subdir_targets+= ${__target}_subdir_${__dir}
${__target}_subdir_${__dir}: .MAKE
@${_+_}set -e; \
if test -d ${.CURDIR}/${__dir}.${MACHINE_ARCH}; then \
@@ -85,7 +90,9 @@ distribute:
fi; \
${MAKE} ${__target:realinstall=install} \
DIRPRFX=${DIRPRFX}$$edir/
+.endif
.endfor
+${__target}: ${__subdir_targets}
.else
${__target}: _SUBDIR
.endif
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