RE: [patch] sched: auto-tune migration costs [was: Re: Industry db benchmark result on recent 2.6 kernels]

["Chen, Kenneth W" <kenneth.w.chen@intel.com>]

Ingo Molnar wrote on Saturday, April 02, 2005 11:04 PM
> the default on ia64 (32MB) was way too large and caused the search to
> start from 64MB. That can take a _long_ time.
>
> i've attached a new patch with your changes included, and a couple of
> new things added:
>
>  - removed the 32MB max_cache_size hack from ia64 - it should now fall
>    back to the default 5MB and do a search from 10MB downwards. This
>    should speed up the search.

The cache size information on ia64 is already available at the finger tip.
Here is a patch that I whipped up to set max_cache_size for ia64.


--- linux-2.6.12-rc1/arch/ia64/kernel/setup.c.orig	2005-04-03 17:14:40.000000000 -0700
+++ linux-2.6.12-rc1/arch/ia64/kernel/setup.c	2005-04-03 17:55:46.000000000 -0700
@@ -561,6 +561,7 @@ static void
 get_max_cacheline_size (void)
 {
 	unsigned long line_size, max = 1;
+	unsigned int cache_size = 0;
 	u64 l, levels, unique_caches;
         pal_cache_config_info_t cci;
         s64 status;
@@ -585,8 +586,11 @@ get_max_cacheline_size (void)
 		line_size = 1 << cci.pcci_line_size;
 		if (line_size > max)
 			max = line_size;
+		if (cache_size < cci.pcci_cache_size)
+			cache_size = cci.pcci_cache_size;
         }
   out:
+	max_cache_size = max(max_cache_size, cache_size);
 	if (max > ia64_max_cacheline_size)
 		ia64_max_cacheline_size = max;
 }