Re: Database regression due to scheduler changes ?

[Brian Twichell <tbrian@us.ibm.com>]

Nick Piggin wrote:

> Just one other thing - A couple of fields aren't actually getting
> initialised at all, which I didn't pick up on.
>
> This bug looks to have been due to a mismerge between the
> common asm-powerpc directory and one of my scheduler changes
> somewhere along the line.
>
> If you get time to try this out, that would be great.
>
>===================================================================
>--- linux-2.6.orig/include/asm-powerpc/topology.h	2005-11-09 16:43:16.000000000 +1100
>+++ linux-2.6/include/asm-powerpc/topology.h	2005-11-09 16:45:17.000000000 +1100
>@@ -51,6 +51,10 @@ static inline int node_to_first_cpu(int 
> 	.cache_hot_time		= (10*1000000),		\
> 	.cache_nice_tries	= 1,			\
> 	.per_cpu_gain		= 100,			\
>+	.busy_idx		= 3,			\
>+	.idle_id		= 1,			\
>+	.newidle_idx		= 2,			\
>+	.wake_idx		= 1,			\
> 	.flags			= SD_LOAD_BALANCE	\
> 				| SD_BALANCE_EXEC	\
> 				| SD_BALANCE_NEWIDLE	\
>  
>
Nick,

That patch eliminates the regression on 2.6.13-rc5.  Thanks !!
We are currently evaluating it with other workloads.

It also gives a boost on 2.6.14, but unfortunately we are still 1%
regressed on 2.6.14.  (The regression on 2.6.14 was larger than
the regression on 2.6.13-rc5.)  We're trying to isolate the 2.6.14
regression now.  I'll let you know if we isolate it to a
scheduler change.

Cheers,
Brian