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Date:      Thu, 31 Jul 1997 21:52:03 -0500
From:      Chris Csanady <ccsanady@friley01.res.iastate.edu>
To:        Andrew Gallatin <gallatin@CS.Duke.EDU>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Myrinet, etc.. (Re: code talks: announcing EIDE bus master patches) 
Message-ID:  <199708010252.VAA15322@friley01.res.iastate.edu>
In-Reply-To: Your message of Thu, 31 Jul 1997 19:54:22 -0400. <199707312354.TAA29288@hurricane.cs.duke.edu> 

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> > I'd also like to point out that the 300Mb's is acheived using an IP
> > stack layered on top of some active messaging protocol. (which is
> > implemented on the io processor on the nic.)
> > 
> > As far as the TCP/IP stack under FreeBSD, all you can push through it
> > is about 150Mb/s.  This is somewhat unfortunate, although surprisingly
> > linux doesn't seem to manage much better.  I think it would be quite
> > nice if we could correctly implement a zero copy architecture..
> > 
> > Chris Csanady
>
>Actually, that's not true.  I'm using an in-kernel IP driver layered
>on top of Myricom's MyriApi general-purpose messaging software (which
>is kernel resident).  It hooks into the network stack the way any
>ethernet driver would (and gets hit with a copy for each xmit from or
>receive into user space like anything else does).  There is software
>that's downloaded onto the interface card, but it has no protocol
>specific knowledge.  When its sitting under the IP driver, it is used
>the same way the firwmware on any ethernet card would be used -- the
>driver tells it a MAC address that it wants something sent to, and it
>sends it, etc.

Sorry, I guess I assumed wrong.  However, the numbers you are
reporting are vastly different from  he ones mentioned  on myrinet's
web page for 2.2.1.

>The fact that we're running over Myrinet & not ethernet is transparent
>to any application.  In this configuration, with the hardware I
>currently have available (memory b/w challenged Pentium Pros) I can
>receive UDP traffic at about 356 Mb/sec and send UDP traffic at a rate
>of a about 280Mb/sec.  TCP streams are around 275Mb/sec.

That really is quite impressive--is your driver available?  I would
like to play with it when I get a chance. :)  I'm also quite
interested in how your interrupt/buffer architecture looks.

As for memory bandwith limitations, I can't wait for the alpha
port. ;)

Chris Csanady



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