From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) (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 2100B3CB3C for ; Thu, 11 Apr 2019 20:04:16 -0400 (EDT) Received: by mail-io1-xd2d.google.com with SMTP id f6so6982143iop.3 for ; Thu, 11 Apr 2019 17:04:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=4Ed7dx3f3cWuKghhPGRsnDzjFCblM6+SF2ms8ZZQ9r0=; b=Bn2P4anbr0ImwT/AQ5N/OlhhpPnl1Qz/uf1q7lKjJ6Qt2iGNBEgewTAp0jX/8Ugxwk 7WTehsLRpJVT4C0y5WFiQ1lr99NrqR8iMM/PbwrEXJd3zvN1+kPfD4Y5goR5nBNFmTTO 6Jt8wX232YWaouPR+qCvNd68suyMNVOVmDW5ZvL5wQ1Wd/zXTEywFjZFeIkaUsXrFY+7 aEBBlHuIbgc5zlwIimoOpGP9YzWJXcAmk9RSEMFz5wt5YuGHIfM4PV/M/c8qRqNj8z7Y yxFcxbZIsQ33rumDjnY4XpUKRHgaQtfJMlBr/20wzcI9vs/BlRdDRCL4QGqInuL/i9nU ui0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=4Ed7dx3f3cWuKghhPGRsnDzjFCblM6+SF2ms8ZZQ9r0=; b=OLmN+na+Hh6TMBmypwtV5O3H1nW5XAM7tAK7pURmpB5h8tyVc/UT0nHt/5wHIHySJg orOFibj0hZrDXEV+puWmp/WyTBNPCuxQqgOVEcC2VVn5UCGierqNwaQxz3KQ5mp6XPe9 iuy9wolTI5IT5j9KEQx1Mu5JDLwR6jMSkiJumjwiQmessVx6Hi7edCJQrs0UCt832ZiC d19LXxqjTzykBOYi1L5Sc+mfLwipbFLeyjL85hd1Npd7KehM98LkwJCUGReScnWyIIm/ Cv+Ff4oP2iAQlOU4xe9jkqU1H5T+d1U9X5w4vtkX9UhQXsGKAi7C5hVVx0r13XqToZGs q7TA== X-Gm-Message-State: APjAAAUeXhUjrrdvyFRuHti1VG+BdR2I8+8qTnIgIzvmjjQXov/CZp4w SAUT1QJIw9b7SqElGrn3exZXA17Mf6YT2VKwTSBEpaSX X-Google-Smtp-Source: APXvYqwE4+mfFeg5ntFTJGs4O7sbdjG4aEO00rE5LJAUb681jlisZnwwOk7aK91M76i9VCsSg6zn+ugJeBdmWxqENPE= X-Received: by 2002:a5e:9e02:: with SMTP id i2mr633147ioq.238.1555027455389; Thu, 11 Apr 2019 17:04:15 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Joshua Zhao Date: Thu, 11 Apr 2019 17:04:04 -0700 Message-ID: To: make-wifi-fast@lists.bufferbloat.net Content-Type: multipart/alternative; boundary="0000000000001838e605864a0b0e" X-Mailman-Approved-At: Thu, 11 Apr 2019 20:05:05 -0400 Subject: Re: [Make-wifi-fast] tx queue stuck for many minutes 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: Fri, 12 Apr 2019 00:04:16 -0000 --0000000000001838e605864a0b0e Content-Type: text/plain; charset="UTF-8" and, BTW, what's best way to disable or skip AQM for comparison purposes? Thanks! Joshua On Thu, Apr 11, 2019 at 4:38 PM Joshua Zhao wrote: > Hi, > I run into a weird symptom that occasionally the aqm tx queue can get > stuck for quite long time (maybe around 30min). What happened is that > we're sending a low bandwidth UDP traffic from the host to multiple peers > over a WiFi radio simultaneously. We're running opensource mac80211 + > ath10k driver. Very occasionally when there are temporary issues causing > trouble on the host sending to one of the peers, the queue to all peers can > get stuck and stay stuck for quite long (even though the link trouble had > been gone or TX had been stopped). Only after quite a while, then the queue > cleans up. > The following dump shows an example that the backlog-packets count stays > at 74 for around 30min after the TX had totally stopped. Here when video > queue is stuck, other TID's traffic can go through. > I wonder why it takes so long for the queue to clean up. Shouldn't packets > be dropped quickly if they cannot be sent? > > Many thanks! > > cat /sys/kernel/debug/ieee80211/phy0/netdev:wlan3/stations/xx:xx:xx/aqm > > target 19999us interval 99999us ecn yes > > tid ac backlog-bytes backlog-packets new-flows drops marks overlimit > collisions tx-bytes tx-packets > > 0 2 0 0 3 0 0 0 0 390 3 > > 1 3 0 0 0 0 0 0 0 0 0 > > 2 3 0 0 0 0 0 0 0 0 0 > > 3 2 0 0 0 0 0 0 0 0 0 > > 4 1 0 0 0 0 0 0 0 0 0 > > 5 1 112344 74 1627 0 0 0 0 2373618 1632 > > 6 0 0 0 0 0 0 0 0 0 0 > > 7 0 0 0 1 0 0 0 0 32 1 > > 8 2 0 0 0 0 0 0 0 0 0 > > 9 3 0 0 0 0 0 0 0 0 0 > > 10 3 0 0 0 0 0 0 0 0 0 > > 11 2 0 0 0 0 0 0 0 0 0 > > 12 1 0 0 0 0 0 0 0 0 0 > > 13 1 0 0 0 0 0 0 0 0 0 > > 14 0 0 0 0 0 0 0 0 0 0 > > 15 0 0 0 0 0 0 0 0 0 0 > > > > --0000000000001838e605864a0b0e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
and, BTW, what's best way to disable or skip AQM for c= omparison purposes?

Thanks!
Joshua
=
On Thu= , Apr 11, 2019 at 4:38 PM Joshua Zhao <swzhao@gmail.com> wrote:
Hi,
I run into a weird symptom that= occasionally the aqm tx queue can get stuck for quite long time (maybe aro= und 30min).=C2=A0 What happened is that we're sending a low bandwidth U= DP traffic from the host to multiple peers over a WiFi radio simultaneously= . We're running opensource mac80211=C2=A0+ ath10k driver. Very occasion= ally when there are temporary issues causing trouble on the host sending to= one of the peers, the queue to all peers can get stuck and stay stuck for = quite long (even though the link trouble had been gone or TX had been stopp= ed). Only after quite a while, then the queue cleans up.
The foll= owing dump shows an example that the backlog-packets count stays at 74 for = around 30min after the TX had totally stopped. Here when video queue is stu= ck, other TID's traffic can go through.=C2=A0
I wonder why it= takes so long for the queue to clean up. Shouldn't packets be dropped = quickly if they cannot be sent?

Many thanks!
cat /sys/kernel/debug/ieee80211/phy0/netdev:wlan3/stations/xx:xx:xx/aqm
target 19999us interval 99999us ecn yes

tid ac backlog-bytes b= acklog-packets new-flows drops marks overlimit collisions tx-bytes tx-packe= ts

0 2 0 0 3 0 0 0 0 390 3

1 3 0 0 0 0 0 0 0 0 0

2 3 0= 0 0 0 0 0 0 0 0

3 2 0 0 0 0 0 0 0 0 0

4 1 0 0 0 0 0 0 0 0 0<= br>
5 1 112344 74 1627 0 0= 0 0 2373618 1632

6 0 0 0 0 0 0 0 0 0 0

7 0 0 0 1 0 0 = 0 0 32 1

8 2 0 0 0 0 0 0 0 0 0

9 3 0 0 0 0 0 0 0 0 0

1= 0 3 0 0 0 0 0 0 0 0 0

11 2 0 0 0 0 0 0 0 0 0

12 1 0 0 0 0 0 0= 0 0 0

13 1 0 0 0 0 0 0 0 0 0

14 0 0 0 0 0 0 0 0 0 0

1= 5 0 0 0 0 0 0 0 0 0 0



--0000000000001838e605864a0b0e--