RE: Accelerated TCP/IP support from kernel

[Gerhard Mack]

I'm curious.. do your cards support IPv6 and ECN ?

	Gerhard

On Thu, 24 May 2001, Bharath Madhavan wrote:

> Thanks a lot. That was useful info especially your last point
> where you are saying that most of the area we can save is in
> data processing and not in protocol processing.
> So, if we use the ZERO_COPY feature, we should gain quite a bit.
> I guess 3c905c NIC supports HW checksumming. Is this true?
> In this case, do we have any benchmarking for this card 
> with and without ZERO_COPY (and HW checksumming). I am eager to
> know by how many times did the system throughput increase?
> Thanks a lot
> Bharath
> 
> 
> 
> 
> -----Original Message-----
> From: David S. Miller [mailto:[e-mail]]
> Sent: Thursday, May 24, 2001 6:29 PM
> To: Bharath Madhavan
> Cc: [e-mail]
> Subject: Re: Accelerated TCP/IP support from kernel
> 
> 
> 
> Bharath Madhavan writes:
>  > 	I am looking into a scenario where we have a NIC which performs 
>  > all the TCP/IP processing and basically the core CPU offloads all data
> from
>  > the socket level interface onwards to this NIC. 
> 
> Why would you ever want to do this?
> 
> Point 1: Support for new TCP techniques and bug fixes are hard enough
> to propagate to user's systems as it is with the implementation being
> done in software.
> 
> Point 2: If I find a bug in the cards TCP implementation, will I be
> able to get at the source for the firmware and fix it?  Likely the
> answer to this is no.
> 
> Every couple years a few vendors make cards like this, yet ignore
> these core issues.  It is currently impractical to use these kinds of
> cards today except in a few very special case situations.
> 
> Furthermore, the actual protocol processing overhead is quite small
> and almost neglible especially on today's gigahertz beasts.  The data
> copy is where the time is spent, and checksum offload takes care of
> that.
> 
> Later,
> David S. Miller
> [e-mail]
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--
Gerhard Mack

[e-mail]

<>< As a computer I find your faith in technology amusing.