adjust p4 per-cpu gain

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.

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
===================================================================
@@ -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	\