Delayed ACK triggered by Header Prediction
demizu at dd.iij4u.or.jp
Wed Mar 16 05:30:57 PST 2005
Thank you very much for your reply.
Actually, I am using GbE on my DragonFlyBSD box.
Here is my experimental environment.
Sender (FreeBSD Stable) --- Router (FreeBSD 5.3R) --- Receiver (DragonFlyBSD)
(Bandwidth = 100Mbps, RTT = 100ms, router queue length = 64 pkts.
On the router above, dummynet runs with HZ=1000.)
All ethernet interfaces above are Broadcom BCM5703 GbE. So, there is
a possibility that receive interrupts for ACK segments are aggregated.
I think TCP performance reduction is due to bandwidth-delay product.
In my environment, if slow start grew slowly, the TCP performance
became poor. I am sorry I did not describe my experimental environment.
I should do so. It was important information in my story.
I have not experienced DragonFlyBSD on normal LAN. I did not talk
about the performance on LAN. I am sorry for my ambiguous report.
Today, I took many packet traces of my experiments. But they have gone...
Tomorrow, I will take another traces and put onto my web page.
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