Re: [PATCH REPOST 1/2] NET: Accurate packet scheduling for ATM/ADSL (kernel)
From: jamal <hidden>
Date: 2006-10-17 13:07:27
On Tue, 2006-17-10 at 09:34 +1000, Russell Stuart wrote:
The Linux traffic's control engine inaccurately calculates transmission times for packets sent over ADSL links. For some packet sizes the error rises to over 50%. This occurs because ADSL uses ATM as its link layer transport, and ATM transmits packets in fixed sized 53 byte cells. This changes the kernel rate table lookup, to be able to lookup packet transmission times over all ATM links, including ADSL, with perfect accuracy. The accuracy is dependent on the rate table that is calculated in userspace by iproute2 command tc. A longer presentation of the patch, its rational, what it does and how to use it can be found here: http://www.stuart.id.au/russell/files/tc/tc-atm/ A earlier version of the patch, and a _detailed_ empirical investigation of its effects can be found here: http://www.adsl-optimizer.dk/ Signed-off-by: Jesper Dangaard Brouer <redacted> Signed-off-by: Russell Stuart <redacted>
ACKed-by: Jamal Hadi Salim When Patrick has his patch ready after this goes in we can revisit. cheers, jamal