Date: Wed, 17 Dec 1997 10:22:42 +1030 From: Mike Smith <mike@smith.net.au> To: jak@cetlink.net (John Kelly) Cc: Mike Smith <mike@smith.net.au>, FreeBSD Hackers <hackers@FreeBSD.ORG> Subject: Re: 3com 3c509 card Message-ID: <199712162352.KAA00272@word.smith.net.au> In-Reply-To: Your message of "Tue, 16 Dec 1997 09:57:47 GMT." <34974fcb.31632460@mail.cetlink.net>
next in thread | previous in thread | raw e-mail | index | archive | help
> 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199712162352.KAA00272>