From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [45.145.95.4]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 2ED3B3B29E; Tue, 22 Nov 2022 15:53:44 -0500 (EST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1669150422; bh=BY5Axci3HcEGV2GJ3Z6XqU6JTufB68mOWUSiTE7OWdw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=wQFqawvULboHdCe06mryOl8HYU+7zCET5TflJ2SCsBNs8TKajy9rxp7qL0mNHty1o uxs3De1Ny5E2c/MxjMV3kgowjXbYfBcnMhVBlSheOCnFvJSjEdR1dg/YeT/GMUKfqO S9GaV/uUDXMXAQhJVSPdCmAldiYGgYQU+P/NALzZ+drXbtLtDaKs8dvfnnLTxYr/V3 DFeGKhOlWO5MnHC6L1RYQ0Evwlkgv4zn7aMFwGrC8Dqrrq/gq5X1qYhQHLp2NZ9JdG O9Rv8ZA0cIQ/G6FobtZn5DXSfDYv2kVV4rb0XmDpvgCW414JLu/6oum8oXO0VXW/B0 fEqSnH1JU7+tQ== To: Neal Cardwell , Bob McMahon Cc: Make-Wifi-fast , BBR Development , bloat In-Reply-To: References: Date: Tue, 22 Nov 2022 21:53:42 +0100 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87r0xuvhgp.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Make-wifi-fast] [Bloat] [bbr-dev] Aggregating without bloating - hard times for tcp and wifi X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Nov 2022 20:53:44 -0000 Neal Cardwell via Bloat writes: > On Tue, Nov 22, 2022 at 2:43 PM 'Bob McMahon' via BBR Development < > bbr-dev@googlegroups.com> wrote: > >> Thanks for sharing this. Curious about how the xTSQ value can be set? Can >> it be done with sysctl? >> >> *We continue our analysis by using the ms-version of TSQ patch, which >> enables the tune of the TSQ size allowing each TCP variant to enqueue more >> than 1 ms of data at the current TCP rate. In particular, we allow to >> enqueue the equivalent of x ms of data, naming each test xTSQ, with x being >> an integer value. It is important to notice that this patch has been >> included in the Linux kernel mainline, and each Wi-Fi driver can now set >> the desired xTSQ value**.* >> > > I believe they are setting the xTSQ value using the sk_pacing_shift field, > which was added here: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3a9b76fd0db9f0d426533f96a68a62a58753a51e > > AFAIK the intent is only for drivers to set that, and there's no sysctl for > that, but of course you could add a sysctl for testing if you wanted. > :-) Yup, indeed this is what mac80211 fiddles with: https://elixir.bootlin.com/linux/latest/source/net/mac80211/main.c#L739 https://elixir.bootlin.com/linux/latest/source/net/mac80211/tx.c#L4156 AFAICT, no in-tree drivers override the value set by mac80211. I believe the tests in that paper were conducted with this series applied: https://lore.kernel.org/all/20180105113256.14835-1-natale.patriciello@gmail.com/ -Toke