Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH RFC/RFT 4/4] mac80211: Apply Airtime-based Queue Limit
 (AQL) on packet dequeue
From:   Peter Oh <peter.oh@eero.com>
To:     Ben Greear <greearb@candelatech.com>,
        =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= <toke@redhat.com>,
        Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org,
        make-wifi-fast@lists.bufferbloat.net,
        John Crispin <john@phrozen.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>
References: <156889576422.191202.5906619710809654631.stgit@alrua-x1>
 <156889576869.191202.510507546538322707.stgit@alrua-x1>
 <f21b10fd-02ae-af59-8e2f-88f654627ab3@eero.com>
 <879913e9-4254-1381-07f6-d860fb0b8de0@candelatech.com>
 <f9b224a0-305f-9715-f627-7a5fae0988d3@eero.com>
Message-ID: <df105ac6-833b-4a22-9ecc-484513a2eb9c@eero.com>
Date:   Thu, 19 Sep 2019 11:03:23 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <f9b224a0-305f-9715-f627-7a5fae0988d3@eero.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk


On 9/19/19 10:54 AM, Peter Oh wrote:
>
> On 9/19/19 10:46 AM, Ben Greear wrote:
>> On 9/19/19 10:44 AM, Peter Oh wrote:
>>> On 9/19/19 5:22 AM, Toke Høiland-Jørgensen wrote:
>>>> From: Toke Høiland-Jørgensen <toke@redhat.com>
>>>>
>>>> This patch ports that idea over to mac80211. The basic idea is simple
>>>> enough: Whenever we dequeue a packet from the TXQs and send it to the
>>>> driver, we estimate its airtime usage, based on the last recorded 
>>>> TX rate
>>>> of the station that packet is destined for.
>>>
>>> The way to decide the last recorded TX rate could be vary among 
>>> drivers. In terms of ath10k driver and FW, they use 4 PPDUs to 
>>> update the Tx rate. Isn't it too small sampling number to be used 
>>> for AQL?
>>
>> Probably it is not exactly the last 4 either, since the report comes 
>> back indirectly and not
>> synchronized with the tx path?
>>
The point of my question is "the last recorded Tx rate is derived from 
small number of PPDUs and if it's OK to use it for AQL calculation or not".

Thanks,

Peter