netdev - Re: [PATCH: 2.6.13-15-SMP 3/3] network: concurrently run softirq network code on SMP

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Message-Id: <1190375023.4261.34.camel@localhost>
Date:	Fri, 21 Sep 2007 07:43:43 -0400
From:	jamal <hadi@...erus.ca>
To:	John Ye <johny@...mco.com.cn>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	kuznet@....inr.ac.ru, pekkas@...core.fi, jmorris@...ei.org,
	kaber@...eworks.de
Subject: Re: [PATCH: 2.6.13-15-SMP 3/3] network: concurrently run softirq
	network code on SMP

On Fri, 2007-21-09 at 17:25 +0800, John Ye wrote:
> David,
> 
> Thanks for your reply. I understand it's not worth to do.
> 
> I have made it a loadable module to fulfill the function. it mainly for busy
> NAT gateway server with SMP to speed up.
> 

John,

It was a little hard to read your code; however, it does seems to me
like will cause a massive amount of packet reordering to the end hosts
using you as the gateway especially when it is receiving a lot of
packets/second. 
You have a queue per CPU that connects your bottom and top half and
several CPUs that may service a single NIC in your bottom half.
one cpu in either bottom/top half has to be slightly loaded and you
loose the ordering where incoming doesnt match outgoing packet order. 

cheers,
jamal

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