Return-path: Received: from mail-oi0-f54.google.com ([209.85.218.54]:36262 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbcEFFvR convert rfc822-to-8bit (ORCPT ); Fri, 6 May 2016 01:51:17 -0400 Received: by mail-oi0-f54.google.com with SMTP id x201so128176985oif.3 for ; Thu, 05 May 2016 22:51:16 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1460636302-31161-1-git-send-email-michal.kazior@tieto.com> <1462446039-1070-1-git-send-email-michal.kazior@tieto.com> <1462446039-1070-6-git-send-email-michal.kazior@tieto.com> Date: Thu, 5 May 2016 22:51:16 -0700 Message-ID: (sfid-20160506_075121_256444_0C90ACA1) Subject: Re: [PATCHv4 5/5] mac80211: add debug knobs for codel From: Dave Taht To: Michal Kazior Cc: linux-wireless , Johannes Berg , make-wifi-fast@lists.bufferbloat.net, "codel@lists.bufferbloat.net" , Avery Pennarun Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, May 5, 2016 at 10:27 PM, Michal Kazior wrote: > On 5 May 2016 at 17:21, Dave Taht wrote: >> On Thu, May 5, 2016 at 4:00 AM, Michal Kazior wrote: >>> This adds a few debugfs entries to make it easier >>> to test, debug and experiment. >> >> I might argue in favor of moving all these (inc the fq ones) into >> their own dir, maybe "aqm" or "sqm". >> >> The mixture of read only stats and configuration vars is a bit confusing. >> >> Also in my testing of the previous patch, actually seeing the stats >> get updated seemed to be highly async or inaccurate. For example, it >> was obvious from the captures themselves that codel_ce_mark-ing was >> happening, but the actual numbers out of wack with the mark seen or >> fq_backlog seen. (I can go back to revisit this) > > That's kind of expected since all of these bits are exposed as > separate debugfs entries/files. To avoid that it'd be necessary to > provide a single debugfs entry/file whose contents are generated on > open() while holding local->fq.lock. But then you could argue it > should contain all per-sta-tid info as well (backlog, flows, drops) as > well instead of having them in netdev*/stations/*/txqs. > Hmm.. I have not had time to write up todays results to any full extent, but they were pretty spectacular. I have a comparison of the baseline ath10k driver vs your 3.5 patchset here on the second plot: http://blog.cerowrt.org/post/predictive_codeling/ The raw data is here: https://github.com/dtaht/blog-cerowrt/tree/master/content/flent/qca-10.2-fqmac35-codel-5 ... a note: quantum of the mtu (typically 1514) is a saner default than 300, (the older patch I had, set it to 300, dunno what your default is now). and quantum 1514, codel target 5ms rather than 20ms for this test series was *just fine* (but more testing of the lower target is needed) However: quantum "300" only makes sense for very, very low bandwidths (say < 6mbits), in other scenarios it just eats extra cpu (5 passes through the loop to send a big packet) and disables the "new/old" queue feature which helps "push" new flows to flow balance. I'd default it to the larger value. ... In other news, spacex just landed on the barge a few minutes ago. The webcast is still going on https://www.youtube.com/watch?v=L0bMeDj76ig and you can reverse it to the landing. :awesome: > > > Michał -- Dave Täht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org