Re: [dpdk-dev] [PATCH v3 2/2] ethdev: add hierarchical scheduler API

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2017-03-06 16:59, Dumitrescu, Cristian:
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 2017-03-04 01:10, Cristian Dumitrescu:
> > > This patch introduces the generic ethdev API for the traffic manager
> > > capability, which includes: hierarchical scheduling, traffic shaping,
> > > congestion management, packet marking.
> > 
> > We already have some API for QoS. Why integrating them in ethdev?
> > ethdev is an interface for networking drivers.
> > I think the QoS has nothing to do with drivers.
> > If there are some operations to offload in drivers, please identify them
> > and let's add the operations to ethdev.
> > 
> 
> The reason to add to ethdev is because QoS traffic management/hierarchical scheduling is just another TX offload for Ethernet devices. This TX offload is present in NICs, NPUs and SoCs from Broadcom, Cavium, Intel, Mellanox, Netronome, NXP, others.
> 
> The API we currently have in DPDK (librte_sched) is great, but it refers to an implementation for a fixed set of features for a BRAS-like hierarchy. The current abstraction layer proposal is intended to support pretty much any hierarchy and traffic management features such as hierarchical scheduling, traffic shaping, congestion management, marking under the same API. It targets pretty much any implementation, either HW, SW or hybrid; it does support the existing librte_sched library feature set, but it is not limited to it.

OK I better understand now.
You should add this level of explanation in your patch.

However I am reluctant to add an API if there is no user.
I think we should wait to have at least one existing driver implementing
this API before integrating it.
It was the approach of eventdev which has a dedicated next- tree.