From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEBB0C43381 for ; Tue, 5 Mar 2019 15:45:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C849A20684 for ; Tue, 5 Mar 2019 15:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728603AbfCEPpv convert rfc822-to-8bit (ORCPT ); Tue, 5 Mar 2019 10:45:51 -0500 Received: from mail-ed1-f43.google.com ([209.85.208.43]:35401 "EHLO mail-ed1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728590AbfCEPpu (ORCPT ); Tue, 5 Mar 2019 10:45:50 -0500 Received: by mail-ed1-f43.google.com with SMTP id g19so7624517edp.2 for ; Tue, 05 Mar 2019 07:45:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=rxj+mSh+wWBLvZbSVbS2ycCqaXjf5XQapmLLhn9oNTQ=; b=BtruA1gBvzY+bwq4d8NygabznpTRbwah/L2oSKIxZnICBRI9FUtHxpeVruHdTScNWI 5revreWALdlbSt0zzl20l/e5Do+uo138g9d4EvfRZK/5sSd/UkRNL1ukhvDjipeTr16y myywEGIDgPBscAD4rFe62c+SK33YPgVlsNg37seeVMNVWClry5LTXBDaO8ngcL45Ce5q 4alYK2QbQpQC0TWCkbvYlebsF8nBndRZoDinLGhn6aV1EsrIz7v7fXIsIH4SMd0YuJA7 29ALcvPuv2T7a2lHjPAAw3gJ8LidMX6zgBTx2a4g9Jj4fc6e158UoRf2aDPbWsG+Lr+j QuTQ== X-Gm-Message-State: APjAAAXTqK+7HcOxfGmNvBCcKwCr7s4lM1dqXFGFC5k4Yv1D4/b0CJw4 yz6pBDucS7NXLis+QJu1lRNO+g== X-Google-Smtp-Source: APXvYqytgs6Ajs2s0x0Q/WS1LAVHHs16rTlbXSA7hos38jXNuJkoRRDz/Wot08VO0csTRyV7jaNQaA== X-Received: by 2002:a05:6402:1495:: with SMTP id e21mr19772510edv.52.1551800749364; Tue, 05 Mar 2019 07:45:49 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk (alrua-x1.vpn.toke.dk. [2a00:7660:6da:10::2]) by smtp.gmail.com with ESMTPSA id i20sm1474686ejv.26.2019.03.05.07.45.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 05 Mar 2019 07:45:48 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 3F5C4182F35; Tue, 5 Mar 2019 16:45:48 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org Cc: Felix Fietkau , Rajkumar Manoharan , Kan Yan Subject: Re: [RFC/RFT] mac80211: Switch to a virtual time-based airtime scheduler In-Reply-To: <20190215170512.31512-1-toke@redhat.com> References: <20190215170512.31512-1-toke@redhat.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 05 Mar 2019 16:45:48 +0100 Message-ID: <87va0x1g0j.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Toke Høiland-Jørgensen writes: > This switches the airtime scheduler in mac80211 to use a virtual time-based > scheduler instead of the round-robin scheduler used before. This has a > couple of advantages: > > - No need to sync up the round-robin scheduler in firmware/hardware with > the round-robin airtime scheduler. > > - If several stations are eligible for transmission we can schedule both of > them; no need to hard-block the scheduling rotation until the head of the > queue has used up its quantum. > > - The check of whether a station is eligible for transmission becomes > simpler (in ieee80211_txq_may_transmit()). > > The drawback is that scheduling becomes slightly more expensive, as we need > to maintain an rbtree of TXQs sorted by virtual time. This means that > ieee80211_register_airtime() becomes O(logN) in the number of currently > scheduled TXQs. However, hopefully this number rarely grows too big (it's > only TXQs currently backlogged, not all associated stations), so it > shouldn't be too big of an issue. > > Signed-off-by: Toke Høiland-Jørgensen > --- > This is basically the idea I mentioned earlier for a different way to > handle the airtime scheduling. > > I've tested it on ath9k, where it achieves the same fairness and > weighing properties as the old scheduler. It would be good if you could > test it on your ath10k setup, Rajkumar; and all of you please comment on > whether you agree that this is better from an API point of view. So no one has any comments on this? :) -Toke