Disk performance issues in DOMU

[Louis Guillaume <louis%zabrico.com@localhost>]

Hi,

I'm running netbsd-5 DOM0 on an amd64 machine. The machine has 2 scsi 
disks, Ultra 320s, on an LSI U320 controller (mpt). These are RAID-1'd 
together by RaidFrame.

The virtual disks (for the DOMUs) are created using "dd" and are just a 
file on an ffs partition, which is on a raidframe device

I did some benchmarks with bonnie++ and found some wild differences 
between amd64/GENERIC, XEN-DOM0 and XEN-DOMU kernels.

While booted to a GENERIC NetBSD kernel, the performance is ok. At least 
this is where I see the best performance.

XEN DOM-0 is significantly different.

XEN DOM-U is miserable!

The results are below. The other test I would like to do involves 
turning ACPI off for DOM0, but I haven't figured out how to do this yet.

Any help in troubleshooting this would be great. Thanks,

Louis





BONNIE++ RESULTS
================

DOMU - NetBSD/amd64 (netbsd-5)
------------------------------

Version 1.03e       ------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
DOMU           300M 20886  19 17954  13 27890  16 69165  98 367303 100 
+++++ +++
                    ------Sequential Create------ --------Random 
Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP 
/sec %CP
                 16    92   5 +++++ +++   166   0    92   5  1924  99 
 186   5



DOM0 - NetBSD/xen (netbsd-5)
----------------------------

Version 1.03e       ------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
DOM0           300M 91482  99 237856  99 262249  99 66962  99 375810  98 
+++++ +++
                    ------Sequential Create------ --------Random 
Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP 
/sec %CP
                 16  4828  99  6721  99 29095  99  4920  99  6416  99 
5451  99


NetBSD/amd64 GENERIC (netbsd-5)
-------------------------------

Version 1.03e       ------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
GENERIC        300M 110726 100 319967  99 354005 100 75345 100 529250 
100 +++++ +++
                    ------Sequential Create------ --------Random 
Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP 
/sec %CP
                 16  7692 100  9325 100 +++++ +++  7790 100  8877 100 
8597 100