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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04555C433EF for ; Tue, 10 May 2022 18:25:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244757AbiEJS3f (ORCPT ); Tue, 10 May 2022 14:29:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243797AbiEJS3e (ORCPT ); Tue, 10 May 2022 14:29:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 040502A7C00 for ; Tue, 10 May 2022 11:25:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A3C88B81F67 for ; Tue, 10 May 2022 18:25:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C364C385D7; Tue, 10 May 2022 18:25:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652207134; bh=/wrEw/XPtbX7Aa29RfzFLqQ9L9elo+ns/lNVoxwRdQI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=aPLY6S64CdECRAhwnpT+P6Lg+3tOjpWl4QS0jzwFkK+G/HKph/VIe4/NGnPV/uy7/ R1M+0fR/DbgwPWTBJm3pGd9t4oKPZmJszTo8jj3DVRtphMPGBH59ylHSj1/Kzx7G0d 5aMXeKTI2AxBSnNfhgQeUyTZNA1gI15cF+eg1dTYb4xTG/DVvvX1SqMsiT92qzQ48J L3epn1xXXlQyRS0Zd72nXdNGyHRAJTBmW00LnxBVOjPM8uivEQzPLzxHFZh3qgx8sz RqhDuWGFjRS7m6AnUDTJw2GGGCOf+8x5NhuOQhdA4nCWg7H/wVDVv34bilE3JbmdrU cfaLbZHICp2lw== Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id E16FA34E33B; Tue, 10 May 2022 20:25:31 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Alexander Wetzel , Johannes Berg Cc: linux-wireless@vger.kernel.org, Felix Fietkau , Alexander Wetzel Subject: Re: [PATCH] mac80211: Simplify queue selection In-Reply-To: <20220510155828.9406-1-alexander@wetzel-home.de> References: <20220510155828.9406-1-alexander@wetzel-home.de> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 10 May 2022 20:25:31 +0200 Message-ID: <8735hhxn1g.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Alexander Wetzel writes: > I still don't understand why we don't want to use qdisc with the iTXQ > drivers. I now just made sure we don't start using qdiscs with this > patch to start with the least invasive approach. Anyone able to shed > some light on that? Because of aggregation, basically. To build an aggregate you need to be able to pull several packets that has the same STA+TID; if all packets on the interface are just sitting in a qdisc you have no interface to do this. Before switching to TXQs, drivers (the ath9k in particular) would solve this by having another layer of per-sta queueing inside the driver, which was just a dump FIFO that added a bunch of latency. The iTXQs moved that up to mac80211, while doing proper queue management (flow queueing + CoDel derived from the FQ-CoDel qdisc) at the same time; this made the qdisc layer redundant for most purposes, which is why we switched to noqueue by default. -Toke