lkml.org 
[lkml]   [2006]   [Nov]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] dio: lock refcount operations

> zach.brown> that path before the recent dio completion patch set. We
> zach.brown> shouldn't expect significant performance regression from
> zach.brown> returning to the behaviour that existed before the completion
> zach.brown> clean up work.
>
> Are you going to quantify this at all? I think we should.

I spotted some free time on an old dual athlon and got an initial look
at the cpu cost of the dio cleanup patches currently in -mm.

I ran two aio-stress instances doing O_DIRECT 64k sequential reads and
writes to an existing 1gig file on ext3 on an old pata drive. I ran a
pair of cycle soakers measuring cpu load every second. After trimming
out the 8 highest and lowest samples the remaining samples were
averaged. I did this three times against 2.6.19-rc4-mm1 before and
after applying the dio-* patches.

before: 5.02% 5.23% 5.27%
after: 5.27% 5.33% 5.32%

So I'm not *gravely* concerned that we've regressed, but it'd be nice to
measure the impact of the dio-* patches on more capable hardware.

- z
-
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: 2006-11-02 02:55    [W:0.062 / U:1.136 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site