Re: 2.6.19-rc1: Volanomark slowdown

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 ....


-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org