lkml.org 
[lkml]   [2001]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Scalable page cache
"David S. Miller" wrote:
>
> From: Ingo Molnar <mingo@elte.hu>
> Date: Mon, 26 Nov 2001 21:29:39 +0100 (CET)
>
> so i'm not against removing (or improving) the hash [our patch in fact
> just left the hash alone], but the patch presented is not a win IMO.
>
> Maybe you should give it a test to find out for sure :)

umm.. I've never seen any numbers from you, David.

Correct me if I'm wrong, but the pagecache_hash cost is
significant in the following situations:

1: TUX, because its pagecache lookups are not associated with
a page copy. This copy makes the benefits of the patch
unmeasurable with other workloads.

1a: Other sendfile-intensive applications. (Theoretical benefit.
No benchmark results have been seen).

2: NUMA hardware, where the cost of cacheline transfer is much
higher.

ergo, there is no point in futzing with the pagecache_lock *at all*
until either TUX is merged, or we decide to support large-scale
NUMA hardware well, which will require changes in other places.

Prove me wrong. Please.

-
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:13    [W:0.077 / U:4.312 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site