diff options
| author | Ingo Molnar <mingo@elte.hu> | 2008-11-05 16:52:08 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-05 18:04:38 +0100 |
| commit | 9fcd18c9e63e325dbd2b4c726623f760788d5aa8 (patch) | |
| tree | fcc7f3c4b17ff66b62feb72194bc14560d948980 /arch | |
| parent | 02479099c286894644f8e96c6bbb535ab64662fd (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.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 90ac7718469a..4850e4b02b61 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, \ } |