On Wed, 29 May 2013 08:52:04 -0700 Eric Dumazet <[email protected]> wrote:
> On Wed, 2013-05-29 at 15:13 +0200, Jesper Dangaard Brouer wrote: > > I recently discovered that the (traffic control) tc linklayer > > calculations for ATM/ADSL have been broken by: > > commit 56b765b79 (htb: improved accuracy at high rates). > > > > Thus, people shaping on ADSL links, using e.g.: > > tc class add ... htb rate X ceil Y linklayer atm overhead 10 > > > > Will no-longer get ATM cell tax/overhead adjusted. > > > > How can we solve/fix this? > > Perhaps we can change to use the "stab" system instead (as it does > > not seem to be broken by the commit). > > [...] > > stab suffers from the same problem : its table driven, so works only > for packet smaller than a given size. You are referring to GSO/GRO packets. Yes, one must disable GSO for this to work. Regardless ATM/ADSL, you should disable GSO when shaping at low speeds. Sending 64000 byte on a 512Kbit/s takes approx 1 sec. http://netoptimizer.blogspot.dk/2010/12/buffer-bloat-calculations.html > I am not sure it will solve the ATM logic (with the 5 bytes overhead > per 48 bytes cell) Are you talking about, that for GSO frames we are not adding a encap overhead to each "sub" skb. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
