Re: Strange IDE performance change in 2.6.1-rc1 (again)

[Ram Pai]

On Thu, 2004-01-08 at 17:17, Andrew Morton wrote:
> Ram Pai <linuxram@xxxxxxxxxx> wrote:
 
> > 
> > Well this is my theory, somebody should validate it,
> 
> One megabyte seems like far too litte memory to be triggering the effect
> which you describe.  But yes, the risk is certainly there.
> 
> You could verify this with:
> 
 
I cannot exactly reproduce what Pualo Ornati is seeing.

Pualo: Request you to validate the following,

1) see whether you see a regression with files replacing the 
   cat command in your script with
       dd if=big_file of=/dev/null bs=1M count=256

2) and if you do, check if you see a bunch of 'eek' with Andrew's 
        following patch. (NOTE: without reverting the changes
        in filemap.c)

--------------------------------------------------------------------------

--- 25/mm/filemap.c~a   Thu Jan  8 17:15:57 2004
+++ 25-akpm/mm/filemap.c        Thu Jan  8 17:16:06 2004
@@ -629,8 +629,10 @@ find_page:
                        handle_ra_miss(mapping, ra, index);
                        goto no_cached_page;
                }
-               if (!PageUptodate(page))
+               if (!PageUptodate(page)) {
+                       printk("eek!\n");
                        goto page_not_up_to_date;
+               }
 page_ok:
                /* If users can be writing to this page using arbitrary
                 * virtual addresses, take care about potential aliasing

---------------------------------------------------------------------------


Thanks,
RP



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