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Subject: Re: How many copies to get from NIC RX to user read()?
To: hurwitz@lanl.gov (Hurwitz Justin W.)
Date: Wed, 10 Jul 2002 00:11:49 +0100 (BST)
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <Pine.LNX.4.44.0207091625460.2905-100000@alvie-mail.lanl.gov> from "Hurwitz Justin W." at Jul 09, 2002 04:29:35 PM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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> How many times is data copied between the time that it is received at the
> NIC and when the user's call to read() returns the data?

Optimal case for TCP

NIC->buffer (DMA)
buffer->user (CPU)

IFF the TCP checksum can be done by the card

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