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Re: Ping

To: bapper@xxxxxxxxxxxxxxx (Brian Pomerantz)
Subject: Re: Ping
From: slurn@xxxxxxxxxxxxxxxxxxxx (Scott Lurndal)
Date: Fri, 24 Mar 2000 14:44:25 -0800 (PST)
Cc: rawio@xxxxxxxxxxx
In-reply-to: <20000324121207.A12999@skull.piratehaven.org> from "Brian Pomerantz" at Mar 24, 2000 12:12:07 PM
Sender: owner-rawio@xxxxxxxxxxx
> 
> I'm a Linux developer at LLNL and am currently working on squeezing as
> much performance out of a couple of RAID systems on Alpha Linux as I
> possibly can.  Right now I'm working on getting some QLogic QLA2200
> going as well as a rack of 8 Ciprico Rimfire 7010's going.  I guess

There is a driver from qlogic (qla2100.c) in the SGI propack which
performs quite a bit better (and more reliably) than the qlogicfc
driver in the standard linux trees.   (propack is on http://oss.sgi.com)


> the performance numbers under Irix are around 50MB/s writes per
> controller and 90MB/s reads.  I'm hoping to attain this performance or
> better with the rawio patches.  So my question is, is this stuff still

To a certain extent, the performance also depends on the system
chipset - some intel motherboards for example won't do more than
70 or 80 mbytes/sec on the pci bus. 

> being worked on and if so, are there plans on working it into the
> kernel?  I think I saw that Steven Tweedie's work is already in the
> 2.3.xx tree, what sort of difference in performance can I expect
> between the SGI changes and the work that Steven Tweedie has done?

There are two key differences in the sgi raw I/O over what
is in 2.3:

        1) Device naming (/dev/raw pseudo devices in SCT vs. 
                          /dev/rsd* character devices in SGI patch)

        2) I/O size (SCT patch breaks all raw I/O up into 1 or 4k
                     chunks.   SGI patch will issue full sized 
                     I/O's (up to 1Mb per I/O)).

We'll have a 2.3.99pre patch next week sometime.

scott

> 
> 
> BAPper
> 


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