[Buildroot] [PATCH] package-infra: limit the number of // jobs

Yann E. MORIN yann.morin.1998 at free.fr
Thu May 9 22:03:20 UTC 2013


From: "Yann E. MORIN" <yann.morin.1998 at free.fr>

The current code spawns as many jobs as up to twice the number of CPUs.

On small-class machines like laptops, with a limitted amount of memory,
but still a few CPUs (real or hyperthreads), the HDD becomes a bottleneck,
and it becomes almost impossible to do anythiong else while there is a
build in progress.

Limit the number of jobs to the number of CPUs plus one.

Even on fast machines with fast HDDs, this settings keeps the machine
fully busy (for those packages that can build in parallel, of course).

For example, building qemu or the linux kernel kept my hyperthreaded
hexa Core i7 with 18GiB of RAM, busy at 99% (I never ever managed to
get 100% even with more jobs, not even 200); while on my hyperthreaded
dual Core i5 with only 4GiB and a slow HDD, I still topped at 100% CPU,
while still able to do some work involving the HDD.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
---
 package/Makefile.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/Makefile.in b/package/Makefile.in
index a449089..a575f17 100644
--- a/package/Makefile.in
+++ b/package/Makefile.in
@@ -11,7 +11,7 @@ HOSTMAKE :=$(shell which $(HOSTMAKE) || type -p $(HOSTMAKE) || echo make)
 # while waiting on I/O.
 ifeq ($(BR2_JLEVEL),0)
 PARALLEL_JOBS:=$(shell echo \
-	$$((2 * `getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1`)))
+	$$((2 + `getconf _NPROCESSORS_ONLN 2>/dev/null || echo 0`)))
 else
 PARALLEL_JOBS:=$(BR2_JLEVEL)
 endif
-- 
1.8.1.2



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