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Date: Thu, 11 Apr 1996 14:01:06 -0600
From: Nate Williams <nate@sri.MT.net>
Message-Id: <199604112001.OAA04945@rocky.sri.MT.net>
To: bugs@freebsd.netcom.com (Mark Hittinger)
Cc: questions@freebsd.org
Subject: re: Slow 3c590's
In-Reply-To: <199604111839.NAA03641@freebsd.netcom.com>
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> I'm not sure this tid bit applies to the 3c590.
> 
> The other 3c5xx cards I have played with have a firmware setting labelled
> "client mode" and "server mode".
> 
> Naturally I selected "server mode".  Many FreeBSD'ers have made the same
> choice for obvious reasons!
> 
> As it turns out, the "server mode" is a way that 3com artificially throttles
> the number of interrupts you can get per unit time (somehow).  This is to
> allow a novell style server to have some cycles for other things.
> 
> If you set the card to "client mode" then the 3c5xx cards will process 
> interrupts as quickly as they can, without a firmware inhibitor.
> 
> So boot the dos setup tool that comes with your ethernet cards and make sure
> that you've selected "client mode" on all the card (assuming such a setting
> exists on the 3c590).
> 
> Your performance should go from dismal to tolerable. :-)

Be careful.  By setting this and a high baud rate (which performs a
similar task of limiting the # of interrupts) you can cause the card to
go 'too fast' for FreeBSD, causing the # of mbufs to quickly be run out.
This happened on my 3C589B (PC-CARD), so I set the speed to 38400 which
caused it to throttle itself because it thought the machine needed to
service alot of serial interrupts.


Nate