From: Ben Greear Subject: Re: Slow ramp-up for single-stream TCP throughput on 4.2 kernel. Date: Mon, 05 Oct 2015 06:35:53 -0700 Message-ID: <56127CB9.1020100@candelatech.com> References: <560F1672.5000602@candelatech.com> <560F1F74.9010207@candelatech.com> <56105AD2.7070906@candelatech.com> <56115C68.1080803@candelatech.com> <1443979705.32531.71.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Neal Cardwell , netdev , ath10k , Eric Dumazet To: Eric Dumazet Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:36117 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752111AbbJENfz (ORCPT ); Mon, 5 Oct 2015 09:35:55 -0400 In-Reply-To: <1443979705.32531.71.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On 10/04/2015 10:28 AM, Eric Dumazet wrote: > On Sun, 2015-10-04 at 10:05 -0700, Ben Greear wrote: > >> I guess I'll just stop using Cubic. Any suggestions for another >> congestion algorithm to use? I'd prefer something that worked well >> in pretty much any network condition, of course, and it has to work with >> ath10k. >> >> We can also run some tests with 1G, 10G, ath10k, ath9k, and in conjunction >> with network emulators and various congestion control algorithms. > > You could use cubic , but disable or tune HyStart, which is known to be > problematic anyway. > > echo 0 >/sys/module/tcp_cubic/parameters/hystart_detect I ran some more tests this morning. The first bump in the graph has the setting above. Seems to work pretty good. The second is using RENO. Also good, and a small bit of higher over-all throughput (about 555-560Mbps of RX throughput). Third is 'highspeed'. It ramps up quickly, but seems a bit more jagged, and not quite as fast as RENO. > > Or try > > echo 40 >/sys/module/tcp_cubic/parameters/hystart_low_window The last graph is this setting (with hystart_detect set back to 3, which was the default on my system). This is better than stock cubic, but it still is awful compared to the others. http://www.candelatech.com/downloads/tcp_cong_ath10k_2.pdf Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com