From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wr0-f181.google.com ([209.85.128.181]:45058 "EHLO mail-wr0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751017AbeBUTxd (ORCPT ); Wed, 21 Feb 2018 14:53:33 -0500 Received: by mail-wr0-f181.google.com with SMTP id p104so7803998wrc.12 for ; Wed, 21 Feb 2018 11:53:33 -0800 (PST) Subject: Re: [PATCH 0/3] Export TXQ parameters and statistics via nl80211 To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org References: <20180219170224.14816-1-toke@toke.dk> <5A8D3445.3040300@broadcom.com> <87bmgiboan.fsf@toke.dk> From: Arend van Spriel Message-ID: <5A8DCE3B.3000607@broadcom.com> (sfid-20180221_205341_859526_CE5172A7) Date: Wed, 21 Feb 2018 20:53:31 +0100 MIME-Version: 1.0 In-Reply-To: <87bmgiboan.fsf@toke.dk> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2/21/2018 12:00 PM, Toke Høiland-Jørgensen wrote: > Arend van Spriel writes: > >> On 2/19/2018 6:02 PM, Toke Høiland-Jørgensen wrote: >>> This series adds TXQ parameters and statistics that were previously only >>> available through debugfs to the nl80211 userspace interface and the >>> cfg80211 kernel interface. Patches for iw to print the statistics and >>> change the settings are included. >> >> So what is your motivation for having this exposed through nl80211. >> For the average end-user the stats and parameters are fairly fuzzy. > > Two reasons, basically: > > 1. Visibility and statistics; this is basically the same information > that is available at the qdisc layer (with `tc -s qdisc`), but which > has been missing on WiFi interfaces ever sine we switched to the TXQ > structure. Having this available has been quite valuable for > debugging qdisc setups on wired links, and it's not always feasible > to ask users to recompile their kernels with debugfs enabled. > > 2. Having visibility into the queues from userspace makes it possible to > make decisions based upon (e.g.) which stations are currently > backlogged. I'm working on a "policy mode" for the airtime fairness > scheduler which will use this capability. I see. Was just wondering whether there were concrete user-space applications planned to use the information. Cool. >> So can we expect some manual in which is described what parameter >> should be tweaked based on the retrieved statistics. > > Heh, not sure I'll promise a whole manual, but I am happy to write a > blog post (or wiki page if that's better) explaining what these values > mean and what insight one might gain from them. My preference would be to have something on wireless.wiki.kernel.org. Another option might be to add kerneldoc section for this. Regards, Arend