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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-04-05 17:23:58 +0200
committerIngo Molnar <mingo@elte.hu>2011-04-14 08:52:41 +0200
commit317f394160e9beb97d19a84c39b7e5eb3d7815a8 (patch)
tree486f268e9ec010744c17333f0f543da9d3909ff4 /init
parentsched: Restructure ttwu() some more (diff)
downloadlinux-dev-317f394160e9beb97d19a84c39b7e5eb3d7815a8.tar.xz
linux-dev-317f394160e9beb97d19a84c39b7e5eb3d7815a8.zip
sched: Move the second half of ttwu() to the remote cpu
Now that we've removed the rq->lock requirement from the first part of ttwu() and can compute placement without holding any rq->lock, ensure we execute the second half of ttwu() on the actual cpu we want the task to run on. This avoids having to take rq->lock and doing the task enqueue remotely, saving lots on cacheline transfers. As measured using: http://oss.oracle.com/~mason/sembench.c $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done $ echo 4096 32000 64 128 > /proc/sys/kernel/sem $ ./sembench -t 2048 -w 1900 -o 0 unpatched: run time 30 seconds 647278 worker burns per second patched: run time 30 seconds 816715 worker burns per second Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152729.515897185@chello.nl
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig5
1 files changed, 5 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 56240e724d9a..32745bfe059e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -827,6 +827,11 @@ config SCHED_AUTOGROUP
desktop applications. Task group autogeneration is currently based
upon task session.
+config SCHED_TTWU_QUEUE
+ bool
+ depends on !SPARC32
+ default y
+
config MM_OWNER
bool