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| author | dim <dim@FreeBSD.org> | 2014-03-26 22:30:38 +0000 |
|---|---|---|
| committer | dim <dim@FreeBSD.org> | 2014-03-26 22:30:38 +0000 |
| commit | 905ed8bc7562473f1fbb0f4b4ae416d1819c2a6c (patch) | |
| tree | 5be3730536450327733d775b82c832d3f363398c /lib/Makefile | |
| parent | 270892ce0aa34981474cedfa90e120b5971c6e13 (diff) | |
| download | FreeBSD-src-905ed8bc7562473f1fbb0f4b4ae416d1819c2a6c.zip FreeBSD-src-905ed8bc7562473f1fbb0f4b4ae416d1819c2a6c.tar.gz | |
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.
I tested this on a 24-core machine, with make -j48 buildworld (N = 6):
before stddev after stddev
======= ====== ======= ======
real time 1741.1 16.5 959.8 2.7
user time 12468.7 16.4 14393.0 16.8
sys time 1825.0 54.8 2110.6 22.8
(user+sys)/real 8.2 17.1
E.g. the build was approximately 45% faster in real time. On machines
with less cores, or with lower -j settings, the speedup will not be as
impressive. But at least you can now almost max out a machine with
buildworld!
Submitted by: jilles
MFC after: 2 weeks
Diffstat (limited to 'lib/Makefile')
| -rw-r--r-- | lib/Makefile | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile index 41eb9b5..5ef0723 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -276,4 +276,8 @@ afterinstall: ${INSTALL_SYMLINK} ../include ${DESTDIR}/usr/lib/include .endif +.if !make(install) +SUBDIR_PARALLEL= +.endif + .include <bsd.subdir.mk> |
