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| author | Ingo Molnar <mingo@elte.hu> | 2008-11-05 18:52:08 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-05 20:04:38 +0300 |
| commit | 9fcd18c9e63e325dbd2b4c726623f760788d5aa8 (patch) | |
| tree | fcc7f3c4b17ff66b62feb72194bc14560d948980 /include | |
| parent | 02479099c286894644f8e96c6bbb535ab64662fd (diff) | |
| download | linux-9fcd18c9e63e325dbd2b4c726623f760788d5aa8.tar.xz | |
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 'include')
| -rw-r--r-- | include/linux/topology.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/topology.h b/include/linux/topology.h index 2158fc0d5a56..34a7ee0ebed2 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -146,10 +146,10 @@ void arch_update_cpu_topology(void); .wake_idx = 1, \ .forkexec_idx = 1, \ .flags = SD_LOAD_BALANCE \ - | SD_BALANCE_NEWIDLE \ - | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ + | SD_BALANCE_FORK \ | SD_WAKE_AFFINE \ + | SD_WAKE_BALANCE \ | BALANCE_FOR_PKG_POWER,\ .last_balance = jiffies, \ .balance_interval = 1, \ |