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authorIngo Molnar <mingo@elte.hu>2008-11-05 16:52:08 +0100
committerIngo Molnar <mingo@elte.hu>2008-11-05 18:04:38 +0100
commit9fcd18c9e63e325dbd2b4c726623f760788d5aa8 (patch)
treefcc7f3c4b17ff66b62feb72194bc14560d948980 /arch
parent02479099c286894644f8e96c6bbb535ab64662fd (diff)
sched: re-tune balancing
Impact: improve wakeup affinity on NUMA systems, tweak SMP systems Given the fixes+tweaks to the wakeup-buddy code, re-tweak the domain balancing defaults on NUMA and SMP systems. Turn on SD_WAKE_AFFINE which was off on x86 NUMA - there's no reason why we would not want to have wakeup affinity across nodes as well. (we already do this in the standard NUMA template.) lat_ctx on a NUMA box is particularly happy about this change: before: | phoenix:~/l> ./lat_ctx -s 0 2 | "size=0k ovr=2.60 | 2 5.70 after: | phoenix:~/l> ./lat_ctx -s 0 2 | "size=0k ovr=2.65 | 2 2.07 a 2.75x speedup. pipe-test is similarly happy about it too: | phoenix:~/sched-tests> ./pipe-test | 18.26 usecs/loop. | 14.70 usecs/loop. | 14.38 usecs/loop. | 10.55 usecs/loop. # +WAKE_AFFINE on domain0+domain1 | 8.63 usecs/loop. | 8.59 usecs/loop. | 9.03 usecs/loop. | 8.94 usecs/loop. | 8.96 usecs/loop. | 8.63 usecs/loop. Also: - disable SD_BALANCE_NEWIDLE on NUMA and SMP domains (keep it for siblings) - enable SD_WAKE_BALANCE on SMP domains Sysbench+postgresql improves all around the board, quite significantly: .28-rc3-11474e2c .28-rc3-11474e2c-tune ------------------------------------------------- 1: 571 688 +17.08% 2: 1236 1206 -2.55% 4: 2381 2642 +9.89% 8: 4958 5164 +3.99% 16: 9580 9574 -0.07% 32: 7128 8118 +12.20% 64: 7342 8266 +11.18% 128: 7342 8064 +8.95% 256: 7519 7884 +4.62% 512: 7350 7731 +4.93% ------------------------------------------------- SUM: 55412 59341 +6.62% So it's a win both for the runup portion, the peak area and the tail. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/topology.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 90ac7718469..4850e4b02b6 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -154,7 +154,7 @@ extern unsigned long node_remap_size[];
#endif
-/* sched_domains SD_NODE_INIT for NUMAQ machines */
+/* sched_domains SD_NODE_INIT for NUMA machines */
#define SD_NODE_INIT (struct sched_domain) { \
.min_interval = 8, \
.max_interval = 32, \
@@ -169,8 +169,9 @@ extern unsigned long node_remap_size[];
.flags = SD_LOAD_BALANCE \
| SD_BALANCE_EXEC \
| SD_BALANCE_FORK \
- | SD_SERIALIZE \
- | SD_WAKE_BALANCE, \
+ | SD_WAKE_AFFINE \
+ | SD_WAKE_BALANCE \
+ | SD_SERIALIZE, \
.last_balance = jiffies, \
.balance_interval = 1, \
}