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Date: Sun, 3 Sep 1995 09:57:26 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199509022357.JAA17851@godzilla.zeta.org.au>
To: bde@zeta.org.au, dennis@et.htp.com
Subject: Re: novell ne2000 cards with FreeBSD...opinions?
Cc: hackers@freebsd.org
Sender: hackers-owner@freebsd.org
Precedence: bulk

>>Shared memory on my NE2000/WD8013EBT card is 50% faster, but that isn't
>>saying much.  The driver spends half its time bcopying to the shared
>>...
>The bus transfer itself is a pretty small piece of the latency puzzle. But
>with a PIO card you have setup operations for every transfer...whereas with
>shared memory you can access individual bytes and the buffer without setup
>latency.

The `ed' driver does bulk copies in both cases.  Random access would
only be significantly faster if some of the data is never looked at and
none of the data is looked at twice.

Bruce