Re: Database regression due to scheduler changes ?

Brian Twichell
2005-11-14T23:03:49Z

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