From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: tc linklayer ADSL calc broken after commit 56b765b79 (htb: improved accuracy at high rates) Date: Wed, 29 May 2013 15:13:30 +0200 Message-ID: <20130529151330.22c5c89e@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Steven Barth , bloat-JXvr2/1DY2fm6VMwtOF2vx4hnT+Y9+D1@public.gmane.org, Jiri Benc , Felix Fietkau To: Stephen Hemminger , Eric Dumazet , David Miller , j.vimal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Michal Soltys , Mike Frysinger , Jussi Kivilinna , Patrick McHardy , Jiri Pirko Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: bloat-bounces-JXvr2/1DY2fm6VMwtOF2vx4hnT+Y9+D1@public.gmane.org Errors-To: bloat-bounces-JXvr2/1DY2fm6VMwtOF2vx4hnT+Y9+D1@public.gmane.org List-Id: netdev.vger.kernel.org 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). But how do we facilitate a change to use "stab" system (for all the scripts using the old option)? Can we change the iproute2/tc command to handle this transparently, or should we give an error/warning if someone uses "tc" and "linklayer" on a kernel above v.3.8. ? History: - My linklayer ATM changes appeared in kernel 2.6.24 (and iproute2 2.6.25) - The STAB changes appeared in kernel 2.6.27 -- 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