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authorMike Galbraith <efault@gmx.de>2009-09-15 15:07:03 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-15 16:51:16 +0200
commit0ec9fab3d186d9cbb00c0f694d4a260d07c198d9 (patch)
tree07773edcece2dd82a63265e027793fe8b2231960 /arch/sh
parent6bd7821f905a8d6c471f0d6675f5cb7ea448d791 (diff)
downloadlinux-0ec9fab3d186d9cbb00c0f694d4a260d07c198d9.tar.gz
sched: Improve latencies and throughput
Make the idle balancer more agressive, to improve a
x264 encoding workload provided by Jason Garrett-Glaser:

 NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 252.82 fps, 22096.60 kb/s
 encoded 600 frames, 250.69 fps, 22096.60 kb/s
 encoded 600 frames, 245.76 fps, 22096.60 kb/s

 NO_NEXT_BUDDY LB_BIAS
 encoded 600 frames, 344.44 fps, 22096.60 kb/s
 encoded 600 frames, 346.66 fps, 22096.60 kb/s
 encoded 600 frames, 352.59 fps, 22096.60 kb/s

 NO_NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 425.75 fps, 22096.60 kb/s
 encoded 600 frames, 425.45 fps, 22096.60 kb/s
 encoded 600 frames, 422.49 fps, 22096.60 kb/s

Peter pointed out that this is better done via newidle_idx,
not via LB_BIAS, newidle balancing should look for where
there is load _now_, not where there was load 2 ticks ago.

Worst-case latencies are improved as well as no buddies
means less vruntime spread. (as per prior lkml discussions)

This change improves kbuild-peak parallelism as well.

Reported-by: Jason Garrett-Glaser <darkshikari@gmail.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1253011667.9128.16.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/include/asm/topology.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/sh/include/asm/topology.h b/arch/sh/include/asm/topology.h
index 9054e5c0ad54..c8436771e31d 100644
--- a/arch/sh/include/asm/topology.h
+++ b/arch/sh/include/asm/topology.h
@@ -15,13 +15,14 @@
 	.cache_nice_tries	= 2,			\
 	.busy_idx		= 3,			\
 	.idle_idx		= 2,			\
-	.newidle_idx		= 2,			\
+	.newidle_idx		= 0,			\
 	.wake_idx		= 0,			\
 	.forkexec_idx		= 1,			\
 	.flags			= SD_LOAD_BALANCE	\
 				| SD_BALANCE_FORK	\
 				| SD_BALANCE_EXEC	\
 				| SD_BALANCE_WAKE	\
+				| SD_BALANCE_NEWIDLE	\
 				| SD_SERIALIZE,		\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\