[RFC,v4,0/3] Add PIE support for HQoS library

  DPDK sched library is equipped with mechanism that secures it from the bufferbloat problem
which is a situation when excess buffers in the network cause high latency and latency 
variation. Currently, it supports RED for active queue management (which is designed 
to control the queue length but it does not control latency directly and is now being 
obsoleted). However, more advanced queue management is required to address this problem
and provide desirable quality of service to users.

This solution (RFC) proposes usage of new algorithm called "PIE" (Proportional Integral
controller Enhanced) that can effectively and directly control queuing latency to address 
the bufferbloat problem.

The implementation of mentioned functionality includes modification of existing and 
adding a new set of data structures to the library, adding PIE related APIs. 
This affects structures in public API/ABI. That is why deprecation notice is going
to be prepared and sent.

Liguzinski, WojciechX (3):
  sched: add PIE based congestion management
  example/qos_sched: add PIE support
  example/ip_pipeline: add PIE support

 config/rte_config.h                      |   1 -
 drivers/net/softnic/rte_eth_softnic_tm.c |   6 +-
 examples/ip_pipeline/tmgr.c              |   6 +-
 examples/qos_sched/app_thread.c          |   1 -
 examples/qos_sched/cfg_file.c            |  82 ++++-
 examples/qos_sched/init.c                |   7 +-
 examples/qos_sched/profile.cfg           | 196 +++++++----
 lib/sched/meson.build                    |  10 +-
 lib/sched/rte_pie.c                      |  82 +++++
 lib/sched/rte_pie.h                      | 393 +++++++++++++++++++++++
 lib/sched/rte_sched.c                    | 229 +++++++++----
 lib/sched/rte_sched.h                    |  53 ++-
 lib/sched/version.map                    |   3 +
 13 files changed, 888 insertions(+), 181 deletions(-)
 create mode 100644 lib/sched/rte_pie.c
 create mode 100644 lib/sched/rte_pie.h
  

Hi Wojciech,

Thank you for doing this work!

> -----Original Message-----
> From: Liguzinski, WojciechX <wojciechx.liguzinski@intel.com>
> Sent: Monday, July 5, 2021 9:04 AM
> To: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>;
> Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
> Cc: Dharmappa, Savinay <savinay.dharmappa@intel.com>; Ajmera, Megha
> <megha.ajmera@intel.com>
> Subject: [RFC PATCH v4 0/3] Add PIE support for HQoS library
> 
> DPDK sched library is equipped with mechanism that secures it from the
> bufferbloat problem
> which is a situation when excess buffers in the network cause high latency
> and latency
> variation. Currently, it supports RED for active queue management (which is
> designed
> to control the queue length but it does not control latency directly and is now
> being
> obsoleted). However, more advanced queue management is required to
> address this problem
> and provide desirable quality of service to users.

As already mentioned by other reviewers, I don't think RED/WRED is getting obsoleted. This entire paragraph is a bit fuzzy and not really adding much value IMO, I propose to remove it.

> 
> This solution (RFC) proposes usage of new algorithm called "PIE"
> (Proportional Integral
> controller Enhanced) that can effectively and directly control queuing latency
> to address
> the bufferbloat problem.

Please add a link to the public RFC for PIE in this cover letter.

> 
> The implementation of mentioned functionality includes modification of
> existing and
> adding a new set of data structures to the library, adding PIE related APIs.
> This affects structures in public API/ABI. That is why deprecation notice is
> going
> to be prepared and sent.

I think you are stating the obvious here, how about removing this paragraph as well?

> 
> Liguzinski, WojciechX (3):
>   sched: add PIE based congestion management
>   example/qos_sched: add PIE support
>   example/ip_pipeline: add PIE support
> 
>  config/rte_config.h                      |   1 -
>  drivers/net/softnic/rte_eth_softnic_tm.c |   6 +-
>  examples/ip_pipeline/tmgr.c              |   6 +-
>  examples/qos_sched/app_thread.c          |   1 -
>  examples/qos_sched/cfg_file.c            |  82 ++++-
>  examples/qos_sched/init.c                |   7 +-
>  examples/qos_sched/profile.cfg           | 196 +++++++----
>  lib/sched/meson.build                    |  10 +-
>  lib/sched/rte_pie.c                      |  82 +++++
>  lib/sched/rte_pie.h                      | 393 +++++++++++++++++++++++
>  lib/sched/rte_sched.c                    | 229 +++++++++----
>  lib/sched/rte_sched.h                    |  53 ++-
>  lib/sched/version.map                    |   3 +
>  13 files changed, 888 insertions(+), 181 deletions(-)
>  create mode 100644 lib/sched/rte_pie.c
>  create mode 100644 lib/sched/rte_pie.h
> 
> --
> 2.17.1

Regards,
Cristian