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From: "alteriks@gmail.com" <alteriks@gmail.com>
To: pyunyh@gmail.com
Date: Fri, 4 Jun 2010 09:37:11 +0200
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Cc: freebsd-net@freebsd.org
Subject: Re: Is enabling jumbo frames on RTL8111C possible?
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On Thursday, 3 of June 2010 19:20:38 Pyun YongHyeon wrote:
> RealTek no longer releases datasheet so it's hard to know required
> information to support jumbo frame. It seems driver released by
> vendor has magic code which enables jumbo frame as well as DSP 
> fixups. The magic code is very complex and hard to understand the
> meaning. It seems Linux borrowed the magic code from vendor but I
> guess they also don't know what the magic code does and why the
> magic is needed.
> 
> Controllers targeted to servers show very good performance number
> with jumbo frame(e.g. about 990Mbps for bulk TCP transfers) but I'm
> not sure how well consumer controller works with jumbo frame.
> Vendor driver disables checksum offloading when jumbo frame is
> used. This indicates the controller has very small FIFO(less than 1
> jumbo frame size) which in turn means it may show poor performance
> under load.

Thanks for explanation.