Commit 0ec9fab3 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

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: default avatarJason Garrett-Glaser <darkshikari@gmail.com>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1253011667.9128.16.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6bd7821f

arch/ia64/include/asm/topology.h

+3 −2
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ void build_cpu_to_node_map(void); 
	.cache_nice_tries	= 2,			\

	.busy_idx		= 2,			\

	.idle_idx		= 1,			\

	.newidle_idx		= 2,			\

	.newidle_idx		= 0,			\

	.wake_idx		= 0,			\

	.forkexec_idx		= 1,			\

	.flags			= SD_LOAD_BALANCE	\
@@ -87,10 +87,11 @@ void build_cpu_to_node_map(void); 
	.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_NEWIDLE	\

				| SD_BALANCE_EXEC	\

				| SD_BALANCE_FORK	\

				| SD_BALANCE_WAKE	\

arch/powerpc/include/asm/topology.h

+1 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ static inline int pcibus_to_node(struct pci_bus *bus) 
	.cache_nice_tries	= 1,			\

	.busy_idx		= 3,			\

	.idle_idx		= 1,			\

	.newidle_idx		= 2,			\

	.newidle_idx		= 0,			\

	.wake_idx		= 0,			\

	.flags			= SD_LOAD_BALANCE	\

				| SD_BALANCE_EXEC	\

arch/sh/include/asm/topology.h

+2 −1
Original line number Diff line number Diff line
@@ -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,			\

arch/x86/include/asm/topology.h

+1 −3
Original line number Diff line number Diff line
@@ -116,14 +116,12 @@ extern unsigned long node_remap_size[]; 


# define SD_CACHE_NICE_TRIES	1

# define SD_IDLE_IDX		1

# define SD_NEWIDLE_IDX		2

# define SD_FORKEXEC_IDX	0



#else



# define SD_CACHE_NICE_TRIES	2

# define SD_IDLE_IDX		2

# define SD_NEWIDLE_IDX		2

# define SD_FORKEXEC_IDX	1



#endif
@@ -137,7 +135,7 @@ extern unsigned long node_remap_size[]; 
	.cache_nice_tries	= SD_CACHE_NICE_TRIES,			\

	.busy_idx		= 3,					\

	.idle_idx		= SD_IDLE_IDX,				\

	.newidle_idx		= SD_NEWIDLE_IDX,			\

	.newidle_idx		= 0,					\

	.wake_idx		= 0,					\

	.forkexec_idx		= SD_FORKEXEC_IDX,			\

									\

include/linux/topology.h

+1 −1
Original line number Diff line number Diff line
@@ -151,7 +151,7 @@ int arch_update_cpu_topology(void); 
	.cache_nice_tries	= 1,					\

	.busy_idx		= 2,					\

	.idle_idx		= 1,					\

	.newidle_idx		= 2,					\

	.newidle_idx		= 0,					\

	.wake_idx		= 0,					\

	.forkexec_idx		= 1,					\

									\

CRA Git | Maintained and supported by SUSTech CRA and CCSE