[PATCH] adjust p4 per-cpu gain

From: Con Kolivas
Date: Sun Aug 01 2004 - 22:14:12 EST


The smt-nice handling patch is a little too aggressive by not estimating the per cpu gain as high enough for pentium4 hyperthread. This patch changes the per sibling cpu gain from 15% to 25%. The true per cpu gain is entirely dependant on the workload but overall the 2 species of Pentium4 that support hyperthreading have about 20-30% gain.

Patch for 2.6.8-rc2-mm1 attached.

Signed-off-by: Con Kolivas <kernel@xxxxxxxxxxx>

P.S: Anton - For the power processors that are now using this SMT nice infrastructure it would be worth setting this value separately at 40%. Index: linux-2.6.8-rc2-mm1/include/linux/sched.h
===================================================================
--- linux-2.6.8-rc2-mm1.orig/include/linux/sched.h 2004-07-30 22:00:05.000000000 +1000
+++ linux-2.6.8-rc2-mm1/include/linux/sched.h 2004-08-02 13:05:39.753964232 +1000
@@ -636,7 +636,7 @@
.imbalance_pct = 110, \
.cache_hot_time = 0, \
.cache_nice_tries = 0, \
- .per_cpu_gain = 15, \
+ .per_cpu_gain = 25, \
.flags = SD_BALANCE_NEWIDLE \
| SD_BALANCE_EXEC \
| SD_WAKE_AFFINE \

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