[Buildroot] [git commit branch/next] automatically set PARALLEL_JOBS when BR2_JLEVEL is 0
From: Peter Korsgaard <jacmet@sunsite.dk>
Date: 2012-08-02 19:52:49
Subsystem:
the rest · Maintainer:
Linus Torvalds
commit: http://git.buildroot.net/buildroot/commit/?id=5016aa02fb51dbd73461f65ed8c7d9b52539a988 branch: http://git.buildroot.net/buildroot/commit/?id=refs/heads/next When BR2_JLEVEL is 0, set PARALLEL_JOBS to double the number of CPUs detected. This allows one to more or less fully utilize the host system without manually tuning the configuration. Also make 0 the default value for BR2_JLEVEL. Signed-off-by: Nathan Lynch <redacted> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk> --- Config.in | 8 +++++--- package/Makefile.in | 8 ++++++++ 2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/Config.in b/Config.in
index 83f64bb..925c247 100644
--- a/Config.in
+++ b/Config.in@@ -178,10 +178,12 @@ config BR2_DEBIAN_MIRROR endmenu config BR2_JLEVEL - int "Number of jobs to run simultaneously" - default "2" + int "Number of jobs to run simultaneously (0 for auto)" + default "0" help - Number of jobs to run simultaneously + Number of jobs to run simultaneously. If 0, determine + automatically according to number of CPUs on the host + system. config BR2_CCACHE bool "Enable compiler cache"
diff --git a/package/Makefile.in b/package/Makefile.in
index be83ada..1d43aef 100644
--- a/package/Makefile.in
+++ b/package/Makefile.in@@ -6,7 +6,15 @@ HOSTMAKE=$(MAKE) endif HOSTMAKE :=$(shell which $(HOSTMAKE) || type -p $(HOSTMAKE) || echo make) +# If BR2_LEVEL is 0, scale the maximum concurrency with the number of +# CPUs. A coefficient of 2 is used in order to keep processors busy +# while waiting on I/O. +ifeq ($(BR2_JLEVEL),0) +PARALLEL_JOBS:=$(shell echo \ + $$((2 * `getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1`))) +else PARALLEL_JOBS:=$(BR2_JLEVEL) +endif MAKE1:=$(HOSTMAKE) -j1 MAKE:=$(HOSTMAKE) -j$(PARALLEL_JOBS)