[Cerowrt-devel] some kernel updates

Sebastian Moeller moeller0 at gmx.de
Thu Aug 22 20:52:02 EDT 2013

Hi List, hi Jesper,

So I tested 3.10.9-1 to assess the status of the HTB atm link layer adjustments to see whether the recent changes resurrected this feature. 
	Unfortunately the htb_private link layer adjustments still is broken (RRUL ping RTT against Toke's netperf host in Germany of ~80ms, same as without link layer adjustments). On the bright side the tc_stab method still works as well as before (ping RTT around 40ms). 
	I would like to humbly propose to use the tc stab method in cerowrt to perform ATM link layer adjustments as default. To repeat myself, simply telling the kernel a lie about the packet size seems more robust than fudging HTB's rate tables. Especially since the kernel already fudges the packet size to account for the ethernet header and then some, so this path should receive more scrutiny by virtue of having more users?
	Now, I have been testing this using Dave's most recent cerowrt alpha version with a 3.10.9 kernel on mips hardware, I think this kernel should contain all htb fixes including commit 8a8e3d84b17 (net_sched: restore "linklayer atm" handling) but am not fully sure.  
`@Dave is there an easy way to find which patches you applied to the kernels of the cerowrt (testing-)releases? While I have you r attention :) I also tested 3.10.9-1's pie and it is way better than 3.10.6-1's (RRUL ping RTTs around 110 ms instead of 3000ms) but still worse than fq_codel (ping RTTs around 40ms with proper atm link layer adjustments). 
While I am not able to build kernels, it seems that I am able to quickly test whether link layer adjustments work or not. SO aim happy to help where I can :)


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