Hi Grenville,

Thanks for the email and the commit link!

Sorry for the late reply. I was traveling, and also going through the code
which you shared.

I believe the implementation of FQ-PIE in FreeBSD matches the proposed ID
very closely. I checked the code for the following:

1. There is a per queue PIE instance
2. Implementation of ECN support as described in Section 5.1 of RFC 8033 (
https://datatracker.ietf.org/doc/html/rfc8033#section-5.1)
3. Use timestamps as a default approach to calculate queue delay instead of
Little's Law
4. The functionality of FQ to be similar to the one used in FQ-CoDel

and I found that all of the above are the same as mentioned in the ID. I'll
edit the ID and mention this implementation. As of now, the ID mentions two
implementations: Linux and ns-3.

Do you have any measurements performed with this implementation? or any
other material related to this? I see it mentions that this is a beta
implementation, but in case it was used in any real deployment or tested in
live networks?

Thanks and Regards,
Mohit P. Tahiliani

On Tue, Mar 11, 2025 at 6:51 AM grenville armitage via Bloat <
bloat@lists.bufferbloat.net> wrote:

> Hi Mohit,
>
> I wonder what you think of the fq-pie developed for FreeBSD back in 2015
> and merged in May 2016? (commit here
> <https://reviews.freebsd.org/rS300779>.)  It has been too long since I
> last looked, so would love your thoughts on how it aligns (or doesn't) with
> https://datatracker.ietf.org/doc/draft-tahiliani-tsvwg-fq-pie/?
>
> cheers,
> gja
>
> On 2025-03-11 06:01, Mohit P. Tahiliani via Bloat wrote:
>
> Hi all,
>
> I have been working on an Internet Draft on Flow Queue PIE (FQ-PIE) [
> https://datatracker.ietf.org/doc/draft-tahiliani-tsvwg-fq-pie/], and
> recently submitted a revised version.
>
> It has been incorporated into the mainline Linux kernel as a queuing
> discipline (qdisc). Additionally, an implementation of FQ-PIE is available
> in the ns-3 network simulator.
>
> If you have any suggestions or feedback, please let me know.
>
> Thanks and Regards,
> Mohit P. Tahiliani
>
> ---------- Forwarded message ---------
> From: <internet-drafts@ietf.org>
> Date: Tue, Mar 4, 2025 at 12:56 AM
> Subject: New Version Notification for draft-tahiliani-tsvwg-fq-pie-01.txt
> To: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
>
>
> A new version of Internet-Draft draft-tahiliani-tsvwg-fq-pie-01.txt has
> been
> successfully submitted by Mohit Tahiliani and posted to the
> IETF repository.
>
> Name:     draft-tahiliani-tsvwg-fq-pie
> Revision: 01
> Title:    Flow Queue PIE: A Hybrid Packet Scheduler and Active Queue
> Management Algorithm
> Date:     2025-03-03
> Group:    Individual Submission
> Pages:    8
> URL:
> https://www.ietf.org/archive/id/draft-tahiliani-tsvwg-fq-pie-01.txt
> Status:   https://datatracker.ietf.org/doc/draft-tahiliani-tsvwg-fq-pie/
> HTML:
> https://www.ietf.org/archive/id/draft-tahiliani-tsvwg-fq-pie-01.html
> HTMLized:
> https://datatracker.ietf.org/doc/html/draft-tahiliani-tsvwg-fq-pie
> Diff:
> https://author-tools.ietf.org/iddiff?url2=draft-tahiliani-tsvwg-fq-pie-01
>
> Abstract:
>
>    This document presents Flow Queue Proportional Integral controller
>    Enhanced (FQ-PIE), a hybrid packet scheduler and Active Queue
>    Management (AQM) algorithm to isolate flows and tackle the problem of
>    bufferbloat.  FQ-PIE uses hashing to classify incoming packets into
>    different queues and provide flow isolation.  Packets are dequeued by
>    using a variant of the round robin scheduler.  Each such flow is
>    managed by the PIE algorithm to maintain high link utilization while
>    controlling the queue delay to a target value.
>
>
>
> The IETF Secretariat
>
>
>
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