From mboxrd@z Thu Jan 1 00:00:00 1970 From: Markus Trippelsdorf Subject: Re: [PATCH net] net: fq_codel: Fix off-by-one error Date: Sat, 30 Mar 2013 07:53:45 +0100 Message-ID: <20130330065345.GA23938@x4> References: <1364514720-20780-1-git-send-email-subramanian.vijay@gmail.com> <1364569280.5113.21.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Vijay Subramanian , netdev@vger.kernel.org, davem@davemloft.net To: Eric Dumazet Return-path: Received: from ud10.udmedia.de ([194.117.254.50]:57510 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750790Ab3C3HA2 (ORCPT ); Sat, 30 Mar 2013 03:00:28 -0400 Content-Disposition: inline In-Reply-To: <1364569280.5113.21.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On 2013.03.29 at 08:01 -0700, Eric Dumazet wrote: > > Just curious, did you play changing the default limit (10240 packets) ? I did some tests on my home router (running OpenWrt trunk) that is rate- limited with hfsc to the speed of the cable modem. My tests seem to indicate that lowering the default limit to 1024 packets results in much better latency behavior when using bittorrent. With the default limit (10240 packets) I would get huge ping latencies from 600-1200ms when downloading e.g.: http://download.opensuse.org/distribution/12.3/iso/openSUSE-12.3-DVD-x86_64.iso.torrent with hundreds of peers. Setting the limit to 1024 did get the latencies back in check (20-30ms with occasional spikes of ~100ms). fq_codel limit 1024: Host Loss% Snt Last Avg Best Wrst StDev 1. OpenWrt.lan 0.0% 179 0.2 0.3 0.2 1.0 0.1 2. ??? 3. 83-169-179-150-isp.superkabel.de 0.6% 179 13.4 29.3 7.1 214.1 26.1 4. 88-134-192-0-dynip.superkabel.de 0.6% 179 13.5 28.2 7.8 213.9 26.3 5. 88-134-196-230-dynip.superkabel.de 1.1% 179 10.7 27.7 7.5 225.6 26.7 6. 88-134-203-141-dynip.superkabel.de 0.6% 179 18.8 30.4 7.6 216.7 25.2 88-134-203-10-dynip.superkabel.de 88-134-203-6-dynip.superkabel.de 88-134-203-14-dynip.superkabel.de 7. 88-134-201-5-dynip.superkabel.de 0.6% 179 8.4 37.1 7.5 453.5 50.6 8. ??? 9. 209.85.249.182 0.6% 179 11.8 28.5 8.2 185.6 25.4 10. 66.249.95.175 0.6% 179 9.2 34.5 8.3 263.9 31.3 66.249.95.67 11. 64.233.174.29 0.6% 179 13.4 30.6 7.8 297.8 31.7 216.239.48.53 64.233.174.55 12. ??? 13. google-public-dns-a.google.com 0.0% 178 13.7 29.7 7.6 312.7 33.8 fq_codel limit 10240: Host Loss% Snt Last Avg Best Wrst StDev 1. OpenWrt.lan 0.0% 179 0.5 0.3 0.2 0.8 0.1 2. ??? 3. 83-169-179-150-isp.superkabel.de 1.1% 179 13.4 98.9 7.6 888.4 170.0 4. 88-134-192-0-dynip.superkabel.de 1.1% 179 16.8 95.5 8.0 892.5 171.9 5. 88-134-196-230-dynip.superkabel.d 1.1% 179 12.8 96.2 7.7 913.8 173.8 6. 88-134-203-6-dynip.superkabel.de 2.2% 179 38.2 105.9 9.5 926.1 175.9 88-134-203-10-dynip.superkabel.de 88-134-203-14-dynip.superkabel.de 88-134-203-141-dynip.superkabel.de 7. 88-134-201-5-dynip.superkabel.de 1.7% 179 44.0 103.3 8.0 960.6 178.9 8. ??? 9. 209.85.249.182 1.7% 179 20.8 98.7 7.7 900.0 176.1 10. 66.249.95.175 1.7% 179 17.0 100.2 8.1 861.9 174.9 66.249.95.67 11. 64.233.174.55 1.7% 179 50.3 102.6 7.7 826.6 171.7 216.239.48.53 64.233.174.29 12. ??? 13. google-public-dns-a.google.com 1.1% 179 12.5 98.2 8.1 849.8 168.9 -- Markus