From: Ingo Molnar <mingo@elte.hu>
Date: Thu, 29 May 2008 12:32:23 +0000 (+0200)
Subject: sched: re-tune NUMA topologies
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ea3f01f8afd3bc5daff915cc4ea5cc5ea9e7d427;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git
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.
---
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 4bb7074a2c3a..24f3d2282e11 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, \
}