Re: 2.6.19-rc1: Volanomark slowdown

From: Arjan van de Ven
Date: Wed Nov 08 2006 - 10:56:08 EST


On Tue, 2006-11-07 at 10:32 -0800, Tim Chen wrote:
> The patch
>
> [TCP]: Send ACKs each 2nd received segment
> commit: 1ef9696c909060ccdae3ade245ca88692b49285b
> http://kernel.org/git/?
> p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1ef9696c909060ccdae3ade245ca88692b49285b
>
> reduced Volanomark benchmark throughput by 10%.
> This is because Volanomark sends
> short message (<100 bytes) on its TCP
> connections. This patch increases the number of ACKs
> traffic by 3.5 times.
>
> By adopting this patch, we assume that with
> small segment, having short delay is important
> enough that we are willing to reduce bandwidth
> with more ACKs.

I wonder if it's an option to use low priority QoS fields for these acks
(heck I don't even know if ACKs have such fields in their packet) so
that they can get dropped if there are more packets then there is
bandwidth ....


--
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