From owner-freebsd-hackers  Tue Dec 16 15:59:01 1997
Return-Path: <owner-freebsd-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id PAA13114
          for hackers-outgoing; Tue, 16 Dec 1997 15:59:01 -0800 (PST)
          (envelope-from owner-freebsd-hackers)
Received: from word.smith.net.au (vh1.gsoft.com.au [203.38.152.122])
          by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id PAA13063
          for <hackers@FreeBSD.ORG>; Tue, 16 Dec 1997 15:58:14 -0800 (PST)
          (envelope-from mike@word.smith.net.au)
Received: from word (localhost [127.0.0.1])
	by word.smith.net.au (8.8.8/8.8.5) with ESMTP id KAA00272;
	Wed, 17 Dec 1997 10:22:43 +1030 (CST)
Message-Id: <199712162352.KAA00272@word.smith.net.au>
X-Mailer: exmh version 2.0zeta 7/24/97
To: jak@cetlink.net (John Kelly)
cc: Mike Smith <mike@smith.net.au>, FreeBSD Hackers <hackers@FreeBSD.ORG>
Subject: Re: 3com 3c509 card 
In-reply-to: Your message of "Tue, 16 Dec 1997 09:57:47 GMT."
             <34974fcb.31632460@mail.cetlink.net> 
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Date: Wed, 17 Dec 1997 10:22:42 +1030
From: Mike Smith <mike@smith.net.au>
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id PAA13093
Sender: owner-freebsd-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

> On Tue, 16 Dec 1997 19:10:50 +1030, Mike Smith <mike@smith.net.au>
> wrote:
> 
> >> I replaced an NE2000 clone with a SMC Ultra 16, thinking shared memory
> >> would consume far less CPU than PIO with an NE2000.  But it seems to
> >> be about the same.
> >
> >About half.  Please don't confuse anecdotal evidence with measured 
> >results.
> >
> 
> I tested with an FTP transfer and consumed about 45% CPU in both
> cases.  
> 
> I wonder if I'm doing something wrong.

Well, for starters you aren't disclosing your measurement technique.  
It sounds to me as though it's not measuring the relative CPU consumed 
per bytes/datagrams transferred by the driver though.

All you have established is that a known ~50% improvement in the CPU 
utilisation of the driver has not affected the amount of CPU used for 
your FTP transfer.  This should tell you something about how efficient 
the driver is in the first place, especially compared with the other 
operations involved in the transfer.

First thing anyone should learn; how to measure things.  Whether you're 
talking engineering, physics, chemistry or computing; if you don't know 
what you're measuring, the numbers mean nothing.

Marketing, now that's a different story. 8)

mike