Re: [PATCH 1/3] lib: dpdk spec to skip red for ingress policer

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Feb 1, 2023 at 11:19 PM Ori Kam <orika@nvidia.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Jerin Jacob <jerinjacobk@gmail.com>
> > Sent: Friday, 27 January 2023 8:23
> > To: Ori Kam <orika@nvidia.com>
> > Cc: Rakesh Kudurumalla <rkudurumalla@marvell.com>; Stephen Hemminger
> > <stephen@networkplumber.org>; NBU-Contact-Thomas Monjalon
> > (EXTERNAL) <thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@amd.com>;
> > Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>; dev@dpdk.org;
> > NBU-Contact-Adrien Mazarguil (EXTERNAL) <adrien.mazarguil@6wind.com>
> > Subject: Re: [PATCH 1/3] lib: dpdk spec to skip red for ingress policer
> >
> > On Thu, Jan 26, 2023 at 8:43 PM Ori Kam <orika@nvidia.com> wrote:
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Rakesh Kudurumalla <rkudurumalla@marvell.com>
> > > > Sent: Wednesday, 18 January 2023 10:10
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Rakesh Kudurumalla
> > > > > Sent: Tuesday, January 10, 2023 12:12 PM
> > > > > To: Ori Kam <orika@nvidia.com>; Jerin Jacob <jerinjacobk@gmail.com>;
> > > > > Stephen Hemminger <stephen@networkplumber.org>
> > > > > Cc: NBU-Contact-Thomas Monjalon (EXTERNAL)
> > <thomas@monjalon.net>;
> > > > > Ferruh Yigit <ferruh.yigit@amd.com>; Andrew Rybchenko
> > > > > <andrew.rybchenko@oktetlabs.ru>; dev@dpdk.org; NBU-Contact-
> > Adrien
> > > > > Mazarguil (EXTERNAL) <adrien.mazarguil@6wind.com>
> > > > > Subject: RE: [PATCH 1/3] lib: dpdk spec to skip red for ingress policer
> > > > >
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Ori Kam <orika@nvidia.com>
> > > > > > Sent: Monday, December 26, 2022 10:30 PM
> > > > > > To: Jerin Jacob <jerinjacobk@gmail.com>; Stephen Hemminger
> > > > > > <stephen@networkplumber.org>
> > > > > > Cc: Rakesh Kudurumalla <rkudurumalla@marvell.com>; NBU-Contact-
> > > > > Thomas
> > > > > > Monjalon (EXTERNAL) <thomas@monjalon.net>; Ferruh Yigit
> > > > > > <ferruh.yigit@amd.com>; Andrew Rybchenko
> > > > > > <andrew.rybchenko@oktetlabs.ru>; dev@dpdk.org; NBU-Contact-
> > > > Adrien
> > > > > > Mazarguil (EXTERNAL) <adrien.mazarguil@6wind.com>
> > > > > > Subject: [EXT] RE: [PATCH 1/3] lib: dpdk spec to skip red for ingress
> > > > > > policer
> > > > > >
> > > > > > External Email
> > > > > >
> > > > > > ----------------------------------------------------------------------
> > > > > > Hi All,
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Jerin Jacob <jerinjacobk@gmail.com>
> > > > > > > Sent: Thursday, 22 December 2022 7:27
> > > > > > >
> > > > > > > On Thu, Dec 22, 2022 at 8:32 AM Stephen Hemminger
> > > > > > > <stephen@networkplumber.org> wrote:
> > > > > > > >
> > > > > > > > On Thu, 22 Dec 2022 07:09:02 +0530 Rakesh Kudurumalla
> > > > > > > > <rkudurumalla@marvell.com> wrote:
> > > > > > > >
> > > > > > > > > Dropping of packets based on RED can be skipped with meter
> > > > > > > > > action, when RED is configured using
> > > > > > > > > rte_eth_cman_config_set()
> > > > > > > > >
> > > > > > > > > Signed-off-by: Rakesh Kudurumalla
> > <rkudurumalla@marvell.com>
> > > > > > > >
> > > > > > > > Should this be more general and apply to all congestion
> > management
> > > > > > > > options. Assuming the hardware can do something better than
> > RED.
> > > > > > >
> > > > > > > Yes. We can use "enum rte_cman_mode mode" in the descriptor to
> > > > > > > future- proof.
> > > > > >
> > > > > > I'm missing the idea of this new action, I understand that is related
> > > > > > to Jerin congestion patches.
> > > > > > But I fail to see why we need it? Is it to mark some metadata that
> > > > > > will have some effect on the congestion result? (I assume the system
> > > > > > is implemented in the HW)
> > > > >
> > > > > Yes. It is implemented in HW. Congestion management is applied on
> > > > ethdev
> > > > > Rx queue using rte_eth_cman_config() API. Once it is configured, it
> > applies
> > > > to
> > > > > all the packets that steer towards that particular ethdev Rx queue. This
> > > > > feature help to skip the congestion management processing based on
> > the
> > > > > packet color identified by the rte_flow meter object. For example, If
> > one
> > > > Rx
> > > > > queue configured as RED congestion  and application wants to bypass
> > the
> > > > > RED congestion  processing for all GREEN color packet can be expressed
> > > > > though this API proposal.
> > > >
> > > > Hi Ori Kam,
> > > >
> > > > Let me know if above information  would give clear idea on skip RED
> > action
> > >
> > > I think so, to put it in my own words,  when setting this the selected packet
> > is treated as
> > > green packet?
> > >
> > > If so, can we use the meter_color field? If you want the packet to be green
> > just set the
> > > field to green?
> >
> > It is already there in one form. See following in existing header file.
> >
> > /**
> >  * Meter policy
> >  */
> > struct rte_mtr_meter_policy_params {
> >         /**
> >          * Policy action list per color.
> >          * actions[i] potentially represents a chain of rte_flow actions
> >          * terminated by the END action, exactly as specified by the rte_flow
> >          * API for the flow definition, and not just a single action.
> >          */
> >         const struct rte_flow_action *actions[RTE_COLORS];
> > };
> >
> >
> Sorry I'm not sure I understand,
> I know we can have colors in the meter, but this feature is about
> somehow telling the rxq to skip the red packet and treat it as green right?

Yes. When rte_mtr_meter_policy_params::actions[RTE_COLOR_GREEN] set as
RTE_FLOW_ACTION_TYPE_SKIP_CMAN for the given meter object,
it is indicating to SKIP the CMAN configuration applied to the rxq on
the downstream path if meter assigns a GREEN color.
(RQ section is as usual as existing path, either via ethdev RSS or
rte_flow RSS action or rte_fow Queue action).

>
> > >
> > > Best,
> > > Ori
> > >