Re: [PATCH iproute2] tc: add support for FQ-PIE packet scheduler

[Stephen Hemminger <stephen@networkplumber.org>]

On Sat,  1 Feb 2020 12:25:36 +0530
gautamramk@gmail.com wrote:

> From: "Mohit P. Tahiliani" <tahiliani@nitk.edu.in>
> 
> This patch adds support for the FQ-PIE packet Scheduler
> 
> Principles:
>   - Packets are classified on flows.
>   - This is a Stochastic model (as we use a hash, several flows might
>                                 be hashed to the same slot)
>   - Each flow has a PIE managed queue.
>   - Flows are linked onto two (Round Robin) lists,
>     so that new flows have priority on old ones.
>   - For a given flow, packets are not reordered.
>   - Drops during enqueue only.
>   - ECN capability is off by default.
>   - ECN threshold (if ECN is enabled) is at 10% by default.
>   - Uses timestamps to calculate queue delay by default.
> 
> Usage:
> tc qdisc ... fq_pie [ limit PACKETS ] [ flows NUMBER ]
>                     [ target TIME ] [ tupdate TIME ]
>                     [ alpha NUMBER ] [ beta NUMBER ]
>                     [ quantum BYTES ] [ memory_limit BYTES ]
>                     [ ecn_prob PERCENTAGE ] [ [no]ecn ]
>                     [ [no]bytemode ] [ [no_]dq_rate_estimator ]
> 
> defaults:
>   limit: 10240 packets, flows: 1024
>   target: 15 ms, tupdate: 15 ms (in jiffies)
>   alpha: 1/8, beta : 5/4
>   quantum: device MTU, memory_limit: 32 Mb
>   ecnprob: 10%, ecn: off
>   bytemode: off, dq_rate_estimator: off
> 
> Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com>
> Signed-off-by: V. Saicharan <vsaicharan1998@gmail.com>
> Signed-off-by: Mohit Bhasi <mohitbhasi1998@gmail.com>
> Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
> Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
> ---
>  bash-completion/tc   |  12 +-
>  man/man8/tc-fq_pie.8 | 166 +++++++++++++++++++++
>  man/man8/tc.8        |   8 +
>  tc/Makefile          |   1 +
>  tc/q_fq_pie.c        | 341 +++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 526 insertions(+), 2 deletions(-)
>  create mode 100644 man/man8/tc-fq_pie.8
>  create mode 100644 tc/q_fq_pie.c
> 

Overall this looks great, thanks for doing the bash-completion as well.

The only issue is that iproute2 now uses SPDX for license information.
Therefore do not include the legal boilerplate and use SPDX for GPLv2 instead.

Checkpatch sort of identifies this.

WARNING: Missing or malformed SPDX-License-Identifier tag in line 1
#378: FILE: tc/q_fq_pie.c:1:
+/*

WARNING: else is not generally useful after a break or return
#529: FILE: tc/q_fq_pie.c:152:
+			return -1;
+		} else {

total: 0 errors, 3 warnings, 558 lines checked