From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.toke.dk ([52.28.52.200]:35907 "EHLO mail.toke.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726559AbeIKOrL (ORCPT ); Tue, 11 Sep 2018 10:47:11 -0400 From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Johannes Berg , linux-wireless@vger.kernel.org, make-wifi-fast@lists.bufferbloat.net Cc: Rajkumar Manoharan , Felix Fietkau Subject: Re: [PATCH RFC v3 1/4] mac80211: Add TXQ scheduling API In-Reply-To: <1536657605.3224.122.camel@sipsolutions.net> References: <153635803319.14170.10011969968767927187.stgit@alrua-x1> <153635897010.14170.2992498632345986102.stgit@alrua-x1> <1536565717.3224.12.camel@sipsolutions.net> <87musplivy.fsf@toke.dk> <1536577419.3224.50.camel@sipsolutions.net> <87zhwpjzme.fsf@toke.dk> <1536583587.3224.71.camel@sipsolutions.net> <87wortjy8n.fsf@toke.dk> <1536585051.3224.72.camel@sipsolutions.net> <87r2i1jxse.fsf@toke.dk> <1536591110.3224.76.camel@sipsolutions.net> <87muspjt38.fsf@toke.dk> <1536657605.3224.122.camel@sipsolutions.net> Date: Tue, 11 Sep 2018 11:48:37 +0200 Message-ID: <87d0tkjrey.fsf@toke.dk> (sfid-20180911_114843_026263_9BD032C5) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: Johannes Berg writes: > On Mon, 2018-09-10 at 17:00 +0200, Toke H=C3=B8iland-J=C3=B8rgensen wrote: > >> > Do we even need end_schedule()? It's hard to pass multiple things to a >> > single call (do you build a list?), so having >> >=20 >> > start_schedule(), get_txq(), return_txq() >> >=20 >> > would be sufficient? >>=20 >> Well, start_schedule() / end_schedule() would be needed if we are going >> to add locking in mac80211? > > [...] > >> If we decide mac80211 needs to do locking to prevent two threads from >> scheduling the same ac, that would also be needed for the hw-managed >> case? > > Yes, good point. > >> > It seems like not? Basically it seems to me that in the hw-managed >> > case all you need is may_tx()? And in fact, once you opt in you don't >> > even really need *that* since mac80211 can just return NULL from >> > get_skb()? >>=20 >> Yeah, we could just throttle in get_skb(); the separate call was to >> avoid the overhead of the check for every packet. Typically, you'll pick >> a TXQ, then dequeue multiple packets from it in succession; with a >> separate call to may_tx(), you only do the check once, not for every >> packet... > > Yeah, also a good point. > > Still, txq =3D get_txq(txq) doesn't feel right, so better to keep that > separate I think. Right, will do :) -Toke