Re: horrible disk thorughput on itanium

Kurt Garloff
2001-12-09T23:14:29Z

[-- Attachment #1: Type: text/plain, Size: 1075 bytes --]

Hi,

On Thu, Dec 06, 2001 at 11:07:14AM -0500, Greg Hennessy wrote:
> [root@hydra bonnie]# cat bonnie.hydra bonnie.leo
[...]
> --Seeks---
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
> /sec %CPU
> 100 1765 100.0 282891 100.1 377295 100.0 2058 100.0 592709
> 99.5 51920.4 196.5

I bet you have more than 100MB RAM, so you measure memory performance
instead of disk performance in the block reads and writes. Same for seeks.
Don't do that. Always use at least twice you ram size if you're interested
in seeing your disk speed.
Newer bonnies warn you about it. The current release is 1.2.
http://www.garloff.de/kurt/linux/bonnie/

The char reads/writes seem to suffer glibc overhead.
You can use the _unlocked variants with option -u and see whether this makes
a difference.

Regards,
--
Kurt Garloff <garloff@suse.de> Eindhoven, NL
GPG key: See mail header, key servers Linux kernel development
SuSE GmbH, Nuernberg, DE SCSI, Security

[-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --]