From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 036053B2A4; Thu, 24 Nov 2022 11:23:23 -0500 (EST) Received: by mail-wr1-x430.google.com with SMTP id v1so3117886wrt.11; Thu, 24 Nov 2022 08:23:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=ZuoWggjgi1+z/dmsqeHrazjcafsTwNAdm/beC3EsHTQ=; b=I4P7BgSN49210+iW9twj71OQJQfcJ+bIHe2sgg5ua1ji++eReWf7ei/a8zKzZUpE/i kr9TAfdOwxxARzxgWZ8n097sTsN/QHxKW0RaVvka7DE9FiLEG6ZbdekuRvT6Kf8HPEqp 6R348KY5GkjEHXEQpeOpVDg3LytuBpVlsHoqvfLOu6DdpoWSSBk6KCvCYSDgByw8YXR1 43GWe5uPW4TNDcXeNrY5IC5YCuf3RVwHnV+kC0jS8OVr88f+n0iZb6vpv52T9HxmI7QK iz6WARDNC5QHJ1uztBqUE3huIZ4qoto2ZCPXEoay1leQPDlqzgu0/1uucxZUvUKZrMLM cEnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ZuoWggjgi1+z/dmsqeHrazjcafsTwNAdm/beC3EsHTQ=; b=wWXkCEUjFfpQbY2Y03kLF45hggaI78mFwyR/NoHMvBUpxnupX/06RlmBrN4QY+8E4F znjug9lgWkEOskRt7wvLPduXi/3g+AesageA2Rd5CD8auM4p9jFW3XCE2lc9kQ9jzCUu 7lDcXqA8EvRwwsRETQIyAEK2LhNyIelIS2+sAeh/CV2Nwi4y41NeAaGrB3hVoOEvXNdA fCu3c+yOfEMc50vEkU6loYOULHMt1V/4ZfjJTdh7nU4TBiPWa/oWVw9ASR7310P0qIi9 /me7Soa1ORL+WqLXYrox+TFg/VIPr6vsTz0mdeohjauKY1cRt+aJ/xeUXJyOqR+eK0ij cvSw== X-Gm-Message-State: ANoB5pkH1QwBgZ3/BmrAcMGjZ+gAr0RtrQxvzsuaCsQX9aPgN2C2t8Rw yIrjeovp9YbzFdPUJIgSXNDXYZVaF4cnu0XrF54= X-Google-Smtp-Source: AA0mqf4OTytYdZn1IwZZkPhhmV5IH4RqagZnhDBrIviPUrbX8sVlZuTncX+rPuwGb1rYzTthaf/+7jVwZ5tfRfJukHs= X-Received: by 2002:a5d:544f:0:b0:241:d7b1:470f with SMTP id w15-20020a5d544f000000b00241d7b1470fmr10428229wrv.500.1669307002696; Thu, 24 Nov 2022 08:23:22 -0800 (PST) MIME-Version: 1.0 References: <003d01d8ffc5$2ace1a20$806a4e60$@umt.edu.pk> In-Reply-To: <003d01d8ffc5$2ace1a20$806a4e60$@umt.edu.pk> From: Dave Taht Date: Thu, 24 Nov 2022 08:23:08 -0800 Message-ID: To: muhammadahsan@umt.edu.pk Cc: Neal Cardwell , Bob McMahon , Make-Wifi-fast , bloat , BBR Development Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] [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: Thu, 24 Nov 2022 16:23:24 -0000 On Wed, Nov 23, 2022 at 9:25 PM Muhammad Ahsan w= rote: > > Hi dev group guys, > > > > I need to use sysctl to set ms value for net.ipv4.tcp_limit_output_ms . > > > > The TSQ patch attached is not working or letting me do that . I am on lin= ux 5.13.12 Why would you test using a 2 year old kernel? In general I try to compile a net-next or a rc3+ candidate when doing network research. By the time your paper is published, your work is 3 or more years obsolete. Working within a modern kernel you can get in general get help from the netdev mailing list. Admittedly, embedded OSes like openwrt tend to lag a few years behind also (presently at 5.15 for most chipsets). > Manually changing tx_sk_pacing_shift =3D 7; variable in main.c needs to= recompile kernel everytime=E2=80=A6 > > > > I need to have sysctl to control the ms value , to set 2TSQ,4TSQ,8TSQ e= tc for my wifi chipset. One of the reasons why I was reluctant to provide this knob was that it seemed inevitable folk would optimize for bandwidth at all other costs, in a lab environment. We picked numbers for the initial implementations of this that made a good compromise between latency and throughput. Certainly tuning it up would be good, but *first* I try to encourage researchers to emulate real-world conditions, where interference and other stations can cause txop scheduling delays measured in the 100s or 1000s of ms. The flent rtt_fair test, to 4 or more stations, in particular, can be quite revealing and our test results and test benchmarks are here: https://www.cs.kau.se/tohojo/airtime-fairness/ There is MUCH other low hanging fruit in wifi. As one example, if you look at aircaps, you will find a lot of single packet, followed by an aggregate, because the driver accepts and schedules that first packet (and txop) and doesn't wait a little bit to assemble a larger aggregate, essentially wasting a txop. There is still, 7+ years since this preso of mine: https://www.youtube.com/watch?v=3DRb-UnHDw02o&t=3D1591s not a lot of understanding of how aggregation behaves. Furthermore ack-filtering is proving helpful in many scenarios. I am sad to report that the initial mt79 firmware design does not expose per station queues, which are IMHO utterly necessary for low latency in wifi6 and wifi7. I have high hopes for the new qualcomm chips... Anyway, some more links: https://forum.openwrt.org/t/reducing-multiplexing-latencies-still-further-i= n-wifi/133605/ https://forum.openwrt.org/t/aql-and-the-ath10k-is-lovely/59002 While I think that most of the patches I care about are in your 5.13 version, there's stuff scheduled for 6.2 or 6.3, and the AQL mechanism used by the ath10k, mt76, iwl, and now mt79, is proving to be a real barrier to good throughput and latency over wifi. > > > > I will be thankful if anyone can help me in it. > > > > > > Rgds, > > Ahsan > > > > > > > > From: 'Neal Cardwell' via BBR Development > Sent: Wednesday, November 23, 2022 1:10 AM > To: Bob McMahon > Cc: Dave Taht ; Make-Wifi-fast ; bloat ; BBR Development > Subject: Re: [bbr-dev] Aggregating without bloating - hard times for tcp = and wifi > > > > On Tue, Nov 22, 2022 at 2:43 PM 'Bob McMahon' via BBR Development 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 enab= les 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 t= he equivalent of x ms of data, naming each test xTSQ, with x being an integ= er value. It is important to notice that this patch has been included in th= e 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/com= mit/?id=3D3a9b76fd0db9f0d426533f96a68a62a58753a51e > > > > AFAIK the intent is only for drivers to set that, and there's no sysctl f= or that, but of course you could add a sysctl for testing if you wanted. :-= ) > > > > cheers, > > neal > > > > > > > > Another thing that could be interesting is the WiFi aggregation stop reas= ons, e.g. how many times agg stopped per hitting the max mpdu per ampdu vs = the software fifo going empty (i.e. no more packets available to the driver= from the TCP stack) per that TXOP. > > Finally, many (most?) APs are forwarding and feeding packets at at the ha= rdware level so not sure that the linux stack matters as much for an AP bas= ed analysis, particularly when considering multi user transmissions, i.e. m= ultiple WiFi clients are active and sharing TXOPs. > > Bob > > On Mon, Nov 21, 2022 at 10:04 PM Dave Taht wrote: > > This paper came out last month. Good work, really exhaustive look at > two chipsets, multiple congestion controls and the interactions with > TSQ, with > lots and lots of flent. > > https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=3D9772053 > > as for wifi6... don't make me start talking about wifi6... but some of > these tests look like a good baseline to start comparing the ath11k, > mt79, etc.. > > Paper kind of misses the negative impact of AQL in the ath10k (and > most likely also the mt76 and mt79 chips) > > -- > This song goes out to all the folk that thought Stadia would work: > https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-698136666= 5607352320-FXtz > Dave T=C3=A4ht CEO, TekLibre, LLC > > -- > You received this message because you are subscribed to the Google Groups= "BBR Development" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to bbr-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgi= d/bbr-dev/CAA93jw6yJU10wh9ajqX4yW2AvnJPStyWAAcV4%2BoQ8wSGsJgKZA%40mail.gmai= l.com. > > > This electronic communication and the information and any files transmitt= ed with it, or attached to it, are confidential and are intended solely for= the use of the individual or entity to whom it is addressed and may contai= n information that is confidential, legally privileged, protected by privac= y laws, or otherwise restricted from disclosure to anyone else. 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If you received this e-mail in error, please r= eturn the e-mail to the sender, delete it from your computer, and destroy a= ny printed copy of it. > > -- > You received this message because you are subscribed to the Google Groups= "BBR Development" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to bbr-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgi= d/bbr-dev/CAHb6LvrK_exkt_rbukYkF4_hwPXyy9T%2BZNGzdK79x91RrK49Mg%40mail.gmai= l.com. > > -- > You received this message because you are subscribed to the Google Groups= "BBR Development" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to bbr-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgi= d/bbr-dev/CADVnQyn9OSxPcF2JsUHdiWLTvAAdN5vs1uyiRBL0AS8yH8niYw%40mail.gmail.= com. --=20 This song goes out to all the folk that thought Stadia would work: https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-69813666656= 07352320-FXtz Dave T=C3=A4ht CEO, TekLibre, LLC