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authorIngo Molnar <mingo@elte.hu>2008-05-29 14:32:23 +0200
committerIngo Molnar <mingo@elte.hu>2008-05-29 14:46:30 +0200
commitea3f01f8afd3bc5daff915cc4ea5cc5ea9e7d427 (patch)
treee2330451fc9d6cc02840c31be3e4956db7974a76
parentb3137bc8e77962a8e3b4dfdc1bcfd38e437bd278 (diff)
sched: re-tune NUMA topologies
improve the sysbench ramp-up phase and its peak throughput on a 16way NUMA box, by turning on WAKE_AFFINE: tip/sched tip/sched+wake-affine ------------------------------------------------- 1: 700 830 +15.65% 2: 1465 1391 -5.28% 4: 3017 3105 +2.81% 8: 5100 6021 +15.30% 16: 10725 10745 +0.19% 32: 10135 10150 +0.16% 64: 9338 9240 -1.06% 128: 8599 8252 -4.21% 256: 8475 8144 -4.07% ------------------------------------------------- SUM: 57558 57882 +0.56% this change also improves lat_ctx from 6.69 usecs to 1.11 usec: $ ./lat_ctx -s 0 2 "size=0k ovr=1.19 2 1.11 $ ./lat_ctx -s 0 2 "size=0k ovr=1.22 2 6.69 in sysbench it's an overall win with some weakness at the lots-of-clients side. That happens because we now under-balance this workload a bit. To counter that effect, turn on NEWIDLE: wake-idle wake-idle+newidle ------------------------------------------------- 1: 830 834 +0.43% 2: 1391 1401 +0.65% 4: 3105 3091 -0.43% 8: 6021 6046 +0.42% 16: 10745 10736 -0.08% 32: 10150 10206 +0.55% 64: 9240 9533 +3.08% 128: 8252 8355 +1.24% 256: 8144 8384 +2.87% ------------------------------------------------- SUM: 57882 58591 +1.21% as a bonus this not only improves the many-clients case but also improves the (more important) rampup phase. sysbench is a workload that quickly breaks down if the scheduler over-balances, so since it showed an improvement under NEWIDLE this change is definitely good.
-rw-r--r--include/linux/topology.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 4bb7074a2c3..24f3d2282e1 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -166,7 +166,9 @@ void arch_update_cpu_topology(void);
.busy_idx = 3, \
.idle_idx = 3, \
.flags = SD_LOAD_BALANCE \
- | SD_SERIALIZE, \
+ | SD_BALANCE_NEWIDLE \
+ | SD_WAKE_AFFINE \
+ | SD_SERIALIZE, \
.last_balance = jiffies, \
.balance_interval = 64, \
}