Date: Wed, 9 Oct 1996 19:47:50 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: barney@databus.com (Barney Wolff) Cc: hardware@FreeBSD.org Subject: Re: Poor SMC Etherpower 10/100 transfer rates Message-ID: <199610100247.TAA08157@GndRsh.aac.dev.com> In-Reply-To: <325c45a40.4f38@databus.databus.com> from Barney Wolff at "Oct 9, 96 08:26:00 pm"
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> Is it possible the card is trying to do full-duplex Ethernet? I have an > odd data point to contribute. I have an SMC 9332 in an NT box. NT > allows 10 Mb, 100 Mb and 100 Mb full-duplex for it. On a 100 Mb SMC > TigerHub 100, talking to a freebsd 2.1.5-release box with an Intel > Pro-100B, I found that the SMC9332 had to be set in non-full-duplex mode > or performance would be just awful. I'm not sure whether that means > that the hub does not support full-duplex, or freebsd with the Intel > doesn't, or both. Since full-duplex 10 Mb does exist (I think) I wonder > if the card thinks that's what it should be doing. Could be, and FYI, you can't do full-duplex ethernet with a HUB, you need an ethernet SWITCH to do that. Attempting to talk FD with a HUB is going to fail. > Where can I RTFM on flag settings for NICs (is that what link<n> does)? A good place would be /usr/src/sys/pci/if_de.c :-) > With the SMC set properly, I get 6-7MB/sec ftp rate between these two > P6/200 boxes on the 100Mb hub. But even then, I often see a pause of > something like a second just after the start of the transfer. Can't > tell if that's caused by packet loss or what. I wondered about MTU > discovery, but as I read the code it starts with the MTU of the interface, > which is 1500. > > Barney Wolff <barney@databus.com> > -- Rod Grimes rgrimes@gndrsh.aac.dev.com
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