Date: Tue, 27 Jan 1998 19:52:19 -0600 From: Chris Csanady <ccsanady@friley585.res.iastate.edu> To: hutton@ISI.EDU Cc: Amancio Hasty <hasty@rah.star-gate.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Gigabit ethernet cards for FreeBSD? Message-ID: <199801280152.TAA07604@friley585.res.iastate.edu> In-Reply-To: Your message of "Tue, 27 Jan 1998 17:14:10 PST." <199801280114.RAA10116@tnt.isi.edu>
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>> >> >Just wondering if there are any for FreeBSD , how they perform and how >> >much they cost? >> >> Packet Engines makes one, as well as a full duplex repeater. The NIC's >> are somewhere in the $1000-1500 range I believe. As for performance, it's >> not quite gigabit yet. With 2 PPro200's, the TCP performance for larger >> write sizes is still limited to around 20MB/s. > >we also found that TCP performance for the Myrinet (also a gigabit technology) >on PPro200's running FreeBSD was not good - around 160Mbps. >UDP performance was better at around 300Mbps. However, to achieve higher >throughput for host based IP forwarding we developed a driver capable of "peer >DMA". This increased our throughput to 440Mbps. No changes were made to the OS >or protocol stack to achieve this. Ted Faber provided the references in an >earlier email. How are you doing the "peer dma?" Is it zero copy? Although it is possible to get good performance without modifying the stack, this is unfair, imho. There is very little hardware that is as smart as the myrinet boards. They are definately nice.. > >BTW what is the MTU on Gigabit ethernet - 1500? Yes, disappointing isn't it? This alone makes it impossible to do anything reasonably efficient. Now it will most likely be a mediocre technology for high performance networking. It will still be good for backbones though, where individual machines can't push that much data. Is this not reason enough to improve the stack though? Chris
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