From owner-freebsd-hackers@FreeBSD.ORG  Wed Aug 18 09:11:24 2004
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Date: Wed, 18 Aug 2004 13:11:21 +0400 (MSD)
From: Maxim Konovalov <maxim@macomnet.ru>
To: Dennis George <easyeinfo@yahoo.com>
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cc: freebsd-hackers@freebsd.org
Subject: Re: Zero copy Socket
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On Wed, 18 Aug 2004, 01:30-0700, Dennis George wrote:

> Hi all,
>  Is there any limitations in using zero copy socket.... I mean... do
> the sender has to follow any specific protocol (like the packet
> payload should be page alligned or so.) ???

Have you read zero_copy(9) man page?

     For sending data, there are no special requirements or capabilities that
     the sending NIC must have.  The data written to the socket, though, must
     be at least a page in size and page aligned in order to be mapped into
     the kernel.  If it does not meet the page size and alignment constraints,
     it will be copied into the kernel, as is normally the case with socket
     I/O.

-- 
Maxim Konovalov