Subject: disk write performance with softdep
To: None <current-users@NetBSD.org>
From: Kouichirou Hiratsuka <hira@po6.nsk.ne.jp>
List: tech-kern
Date: 04/09/2006 18:27:42
Hello,

On my machine (ThinkPad X32), disk write performance with softdep
is about 4 times as slow as before.  It takes about 3 or 4 times
as long to copy the files.  And with bonnie++, the sequential
output (per char) is 1/4.

It seems to be related to this commit (please see the following
results of bonnie++).

  http://mail-index.NetBSD.org/source-changes/2006/03/30/0021.html

bonnie++ by 2006-03-30 12:00 UTC GENERIC kernel (with softdep):
-------------------------------------------------------------------------------
Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
firefly.locald 300M 44458  68 46395  20 44065  19 62603  99 +++++ +++ +++++ +++
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  3294  95 +++++ +++ +++++ +++  2280  65  5287  97 11461  97
-------------------------------------------------------------------------------

bonnie++ by 2006-03-30 13:00 UTC GENERIC kernel (with softdep):
-------------------------------------------------------------------------------
Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
firefly.locald 300M 11288  25 46092  20 42042  18 59944  94 +++++ +++ +++++ +++
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  3106  92 +++++ +++ +++++ +++  3500  92  4868  99 10719  99
-------------------------------------------------------------------------------

Anyone else seeing this?
-- 
 Kouichirou Hiratsuka
   hira@po6.nsk.ne.jp