[PATCH] sched: adjust p4 per-cpu gain

The smt-nice handling 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.

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%.

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7d8558329e046115be47a256396be430b4c203da..706eb4ac4c81f6077655e4608a8f502d47c3af67 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -626,7 +626,7 @@ struct sched_domain {
        .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        \