Re: Alan Shih: "TCP IP Offloading Interface"

David griego (
Mon, 14 Jul 2003 13:23:12 -0700

>From: Jeff Garzik <>
>To: David griego <>
>Subject: Re: Alan Shih: "TCP IP Offloading Interface"
>Date: Mon, 14 Jul 2003 16:03:01 -0400
>David griego wrote:
>>Intel Clusters and Network Storage Volume Platforms Lab reported that it
>>takes about 1MHz to process 1Mbps on a PIII. Using this rule of thumb
>>(they showed it scaling from 400MHz to 800MHz) it would take 10GHz to
>>process 10Mbps. Well you might say "what about multi-processers?" This
>Um. It doesn't take nearly 10Ghz to handle 10Mbps, or even 100Mbps.
Err. Make that 10GHz for 10Gbps :-)
>>would be good for people that have multi-processors, but there is a large
>>segment of embedded processors that are not going have SMP, or be at 10GHz
>>anytime soon. Besides that processing interrupts does not scale across
>>MPs liniarly. The truth is that communication speeds are outpacing
>>processor speeds at this time.
>If the host CPU is a bottleneck after large-send and checksums have been
>offloaded, then logically you aren't getting any work done _anyway_. You
>have to interface with the net stack at some point, in which case you incur
>a fixed cost, for socket handling, TCP exception handling, etc.
Still other processing going on like RAID, NFS, or CIFS.
>Maybe somebody needs to be looking into AMP (asymmetric multiprocessing),
Nice artical on AMP for ATM. I'll try to find a pointer.
> Jeff

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