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Re: Effect of kiobufs?

To: ppetru@xxxxxxxxxx (Petru Paler)
Subject: Re: Effect of kiobufs?
From: dbl@xxxxxxxxxxxxx (Dave Lounsberry)
Date: Sun, 25 Mar 2001 10:54:37 -0600 (CST)
Cc: linux-xfs@xxxxxxxxxxx
In-reply-to: <20010324131336.A3369@ppetru.net> from "Petru Paler" at Mar 24, 2001 01:13:36 PM
Sender: owner-linux-xfs@xxxxxxxxxxx
Here is what I am seeing on the following system:

        Athlon 1GHZ
        Ultra2 LVD SCSI 10K RPM disk
        256MB Memory

To be sure, I ran it several times. I used a package called bonnie to get these 
numbers. 

- XFS mounted with default mount options
              ---------Sequential Output------------ 
              -Per Char-    --Block---    -Rewrite-- 
              K/sec %CPU    K/sec %CPU    K/sec %CPU 
               6736 84.7    43180 24.9     9902  8.5 

               -----Sequential Input---     --Random--
               -Per Char-    --Block---     --Seeks---
               K/sec %CPU    K/sec %CPU      /sec %CPU
                6284 76.0    57735 26.5     871.6  3.1

- XFS mounted with kio mount option
              -------Sequential Output--------------- 
              -Per Char-     --Block---    -Rewrite-- 
              K/sec %CPU     K/sec %CPU   K/sec %CPU 
               7454 92.0    143541 81.3   101492 79.3

               -----Sequential Input---   --Random--
              -Per Char-    --Block---    --Seeks---
              K/sec %CPU    K/sec %CPU     /sec %CPU
               7785 93.6    262545 92.3    24547.3 98.2

The block level I/O is amazing and actually beyond the capabilities of Ultra2 
SCSI. 
Are these numbers for real????? Ultra2 LVD runs at 80MB/s not 260MB/s. 

Dave Lounsberry
dbl@xxxxxxxxxxxxx

> 
> Hi,
> 
> What are the gains of using the "kio" mount options? Are
> kiobufs faster than buffer heads, or they just allow more
> efficient merging of requests?
> 
> Thanks,
> 
> --
> Petru Paler, mailto:ppetru@xxxxxxxxxx
> http://www.ppetru.net - ICQ: 41817235
> 


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