From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-x331.google.com (mail-ot1-x331.google.com [IPv6:2607:f8b0:4864:20::331]) (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 CC4D13CB37 for ; Tue, 22 Nov 2022 15:10:40 -0500 (EST) Received: by mail-ot1-x331.google.com with SMTP id l42-20020a9d1b2d000000b0066c6366fbc3so10008449otl.3 for ; Tue, 22 Nov 2022 12:10:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=LiIniOyI3R0SepSKoOoBoHzsG7FxlHvJB7U/qlmfGFw=; b=GwsEf74qc82MV3HvNvE0KfYQc+lQmGL1rP6W+2Hm6sWE3DLtNosHkgWfOIF8GN4CvK U/LLmDyScL59pW45aaMIhjNYqY1PKQdO6rpP250IkWo2Drf8gLLhR6ynhzygBd808FFB 476Kz8JEHG6PmVfhFRUEk13yRderVcW0yaxgpUx0Rj/P8wvZCLaiTKJtcrsfbxn3I1xP zu3gn6WSTJz+OuheefaeQNjsd2cr6polbDd7C40UooAHbbKmZDRaZAPtdAiKcwvcAN7R 3EUljJGSb7OzzkIEXILWuVd3BQCkDha7dT8webBGx57qCNyc3ayVJxcv/0FV09AS/4/s h3tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=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=LiIniOyI3R0SepSKoOoBoHzsG7FxlHvJB7U/qlmfGFw=; b=7iY+iFd1hGsSzlesZn38U1/k4l0Z/ezO4akfMhP6RtCkTvb0EDMqlExam3pAVyOppV Zus0QASMyPXb8tH5+KDuIq0BSfma+VkCs/sCr9raaTu5Hmu5uVbtnbn00je4mUkdpdZs fuBMyzgiDwOGdkgEiAGaLzjXK0nzidCZEUW6Vbf4Gd3JFnvpMKnvFTpnF0swgwJ+3rHc FfF2J4CRf9jShjXru3Bj0C6xpW/iWehmhqtPkrP1o7SpF+jiVMPP8ivW8MXvKkbxCXWg YEMQJ14fgJ+IaFbHqjQNK+zpubcNTqrWRNQjuLJ3Vm2KiqsxBlgmWsxN0OFxbPQf0x4v 7w3Q== X-Gm-Message-State: ANoB5pnq1juxdVK28bWYGBWvAWLsoMMLQTQDAlW2fD7djXixARAlBsHF OcwGSMFeWVBLWdxtYsVd1YpCj72hA28sc2v1OIsqIw== X-Google-Smtp-Source: AA0mqf6HIijpbIPDCXleTxR9QLLZlxXfYvgw/lxqF8HUpXHEug6ZgW/MQhOfILpDeCunsx1Z2mqEFsJDqWUzwTMSroQ= X-Received: by 2002:a05:6830:2a0a:b0:66c:3703:f04e with SMTP id y10-20020a0568302a0a00b0066c3703f04emr13051951otu.287.1669147839823; Tue, 22 Nov 2022 12:10:39 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Neal Cardwell Date: Tue, 22 Nov 2022 15:10:23 -0500 Message-ID: To: Bob McMahon Cc: Dave Taht , Make-Wifi-fast , bloat , BBR Development Content-Type: multipart/alternative; boundary="0000000000001270a405ee14c479" Subject: Re: [Bloat] [bbr-dev] Aggregating without bloating - hard times for tcp and wifi X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Nov 2022 20:10:40 -0000 --0000000000001270a405ee14c479 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 mor= e > 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 bei= ng > 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=3D3a9b76fd0db9f0d426533f96a68a62a58753a51e 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. :-) cheers, neal > Another thing that could be interesting is the WiFi aggregation stop > reasons, e.g. how many times agg stopped per hitting the max mpdu per amp= du > 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 > hardware level so not sure that the linux stack matters as much for an AP > based analysis, particularly when considering multi user transmissions, > i.e. multiple 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-69813666= 65607352320-FXtz >> Dave T=C3=A4ht CEO, TekLibre, LLC >> >> -- >> You received this message because you are subscribed to the Google Group= s >> "BBR Development" group. >> To unsubscribe from this group and stop receiving emails from it, send a= n >> email to bbr-dev+unsubscribe@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/bbr-dev/CAA93jw6yJU10wh9ajqX4yW2AvnJPS= tyWAAcV4%2BoQ8wSGsJgKZA%40mail.gmail.com >> . >> > > This electronic communication and the information and any files > transmitted 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 an= d > may contain information that is confidential, legally privileged, protect= ed > by privacy laws, or otherwise restricted from disclosure to anyone else. = If > you are not the intended recipient or the person responsible for deliveri= ng > the e-mail to the intended recipient, you are hereby notified that any us= e, > copying, distributing, dissemination, forwarding, printing, or copying of > this e-mail is strictly prohibited. If you received this e-mail in error, > please return the e-mail to the sender, delete it from your computer, and > destroy any 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/msgid/bbr-dev/CAHb6LvrK_exkt_rbukYkF4_hwPXyy9= T%2BZNGzdK79x91RrK49Mg%40mail.gmail.com > > . > --0000000000001270a405ee14c479 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Tue, Nov 22, 2022 at 2:43 PM 'Bob = McMahon' via BBR Development <bbr-dev@googlegroups.com> wrote:
<= div dir=3D"ltr">Thanks for sharing this. Curious about how the xTSQ value c= an be set? Can it be done with sysctl?

We continue our analysis b= y 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 imp= ortant 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:

AFAIK the intent is = only for drivers to set that, and there's no sysctl for that, but of co= urse you could add a sysctl for testing if you wanted. :-)

cheers,
neal


=C2= =A0
Another thing tha= t could be interesting is the WiFi aggregation stop reasons, e.g. how many = times agg stopped per hitting the max mpdu per ampdu vs the software fifo g= oing empty (i.e. no more packets available to the driver from the TCP stack= ) per that TXOP.

Finally, many (most?) APs are forwarding and feedin= g packets at at the hardware level so not sure that the linux stack matters= as much for an AP based analysis, particularly when considering multi user= transmissions, i.e. multiple WiFi clients are active and sharing TXOPs.
Bob
On Mon, Nov 21, 2022 at= 10:04 PM Dave Taht <dave.taht@gmail.com> 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/stam= p.jsp?arnumber=3D9772053

as for wifi6... don't make me start talking about wifi6... but some of<= br> 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-6981366665607352320-FXt= z
Dave T=C3=A4ht CEO, TekLibre, LLC

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This ele= ctronic communication and the information and any files transmitted with it= , or attached to it, are confidential and are intended solely for the use o= f the individual or entity to whom it is addressed and may contain informat= ion that is confidential, legally privileged, protected by privacy laws, or= otherwise restricted from disclosure to anyone else. If you are not the in= tended recipient or the person responsible for delivering the e-mail to the= intended recipient, you are hereby notified that any use, copying, distrib= uting, dissemination, forwarding, printing, or copying of this e-mail is st= rictly prohibited. If you received this e-mail in error, please return the = e-mail to the sender, delete it from your computer, and destroy any printed= copy of it.

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to bbr-dev+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/bbr-dev/CAHb6LvrK_exkt_rbukYkF4_hwPXyy9= T%2BZNGzdK79x91RrK49Mg%40mail.gmail.com.
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