netdev - Block based abstraction in af

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Date:	Sun, 22 May 2011 13:46:40 -0400
From:	chetan loke <loke.chetan@...il.com>
To:	netdev@...r.kernel.org, loke.chetan@...il.com
Subject: Block based abstraction in af_packet->Rx::mmap

Hello,

With the current af_packet->rx::mmap based approach, the element size
in the block needs to be statically configured.
Nothing wrong with the current config/implementation. But since the
traffic profile cannot be known in advance, it would be nice if that
configuration
wasn't static. Normally, one would configure the element-size
to be '2048' so that you can atleast capture the entire 'MTU-size'.
But if the traffic profile varies then we would end up either
i)wasting memory or ii) end up getting a sliced frame.

In other words the packet density will be much much less in the first case.

Also, today we have to spin-wait/poll if a single packet is ready for
consumption(is status == TP_STATUS_USER?).
This does not scale. Rather, poll-waiting on a single block will
definitely help.

Q1)Is anyone working on enhancing the current mmap implementation?
Q2)Do patches exist for such non-static implementation already?

PS: Please CC me on the replies as I am not subscribed on the mailing list.

Regards
Chetan
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