Subject: Re: Intel i82547 performance problems in wm(4)
To: Mipam <>
From: Bill Studenmund <>
List: tech-net
Date: 07/16/2004 10:33:50
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On Fri, Jul 16, 2004 at 12:14:58PM +0200, Mipam wrote:
> On the internet jumbo frames dont work, so only checksum=20
> offloading can be done. But since that isnt such a complicated operation,=
> it wont boost performance that much i guess, or maybe am i wrong?

My personal experience with an application that spends a lot of time=20
sending data from disk over a TCP socket is that checksum offload (IP and=
TCP) do in fact make a big difference. It helps both with saved cycles=20
(CPU can do other things) and with reduced cache usage (as the data don't=
have to be reloaded into the Dcache to get checksummed). If there is=20
something else the CPU can be doing, then the offload support lets it=20
effectively do two things at once.

Take care,


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