Hi Adrien, Thanks for reviewing this proposal.
> -----Original Message----- > From: Adrien Mazarguil [mailto:adrien.mazarg...@6wind.com] > Sent: Thursday, June 1, 2017 4:14 PM > To: Dumitrescu, Cristian <cristian.dumitre...@intel.com> > Cc: dev@dpdk.org; tho...@monjalon.net; > jerin.ja...@caviumnetworks.com; hemant.agra...@nxp.com; Doherty, > Declan <declan.dohe...@intel.com>; Wiles, Keith <keith.wi...@intel.com> > Subject: Re: [RFC 3/3] rte_flow: add new action for traffic metering and > policing > > Hi Cristian, > > On Tue, May 30, 2017 at 05:44:13PM +0100, Cristian Dumitrescu wrote: > > Signed-off-by: Cristian Dumitrescu <cristian.dumitre...@intel.com> > > --- > > lib/librte_ether/rte_flow.h | 22 ++++++++++++++++++++++ > > 1 file changed, 22 insertions(+) > > > > diff --git a/lib/librte_ether/rte_flow.h b/lib/librte_ether/rte_flow.h > > index c47edbc..2942ca7 100644 > > --- a/lib/librte_ether/rte_flow.h > > +++ b/lib/librte_ether/rte_flow.h > > @@ -881,6 +881,14 @@ enum rte_flow_action_type { > > * See struct rte_flow_action_vf. > > */ > > RTE_FLOW_ACTION_TYPE_VF, > > + > > + /** > > + * Traffic metering and policing (MTR). > > + * > > + * See struct rte_flow_action_meter. > > + * See file rte_mtr.h for MTR object configuration. > > + */ > > + RTE_FLOW_ACTION_TYPE_METER, > > }; > > > > /** > > @@ -974,6 +982,20 @@ struct rte_flow_action_vf { > > }; > > > > /** > > + * RTE_FLOW_ACTION_TYPE_METER > > + * > > + * Traffic metering and policing (MTR). > > + * > > + * Packets matched by items of this type can be either dropped or passed > to the > > + * next item with their color set by the MTR object. > > + * > > + * Non-terminating by default. > > + */ > > +struct rte_flow_action_meter { > > + uint32_t mtr_id; /**< MTR object ID created with rte_mtr_create(). > */ > > +}; > > + > > +/** > > * Definition of a single action. > > * > > * A list of actions is terminated by a END action. > > Assuming this action is provided to the underlying PMD, can you describe > what happens next; what is a PMD supposed to do when creating the flow > rule > and the impact on its data path? > Metering is just another flow action that needs to be supported by rte_flow API. Typically, NICs supporting this action have an array of metering & policing contexts on their data path, which are abstracted as MTR objects in our API. - rte_mtr_create() configures an MTR object, with no association to any of the known flows yet. - On NIC side, the driver configures one of the available metering & policing contexts. - rte_flow_create() defines the flow (match rule) and its set of actions, with metering & policing as one of the actions. - On NIC side, the driver configures a flow/filter for traffic classification/distribution/bifurcation, with the metering & policing context enabled for this flow. At run-time, any packet matching this flow will execute this action, which involves metering (packet is assigned a color) and policing (packet may be recolored or dropped, as configured), with stats being updated as well. > It looks like mtr_id is arbitrarily set by the user calling > rte_mtr_create(), which means the PMD has to look up the associated MTR > context somehow. > > How about making the rte_mtr_create() API return an opaque rte_mtr > object > pointer provided back to all API functions as well as through this action > instead, and not leave it up to the user? > Of course, it can be done this way as well, but IMHO probably not the best idea from the application perspective. We had a similar discussion when we defined the ethdev traffic management API [1]. Object handles can be integers, void pointers or pointers to opaque structures, and each of these approaches are allowed and used by DPDK APIs. Here is an example why I think using integers for MTR object handle makes the life of the application easier: - Let's assume we have several actions for a flow (a1, a2, a3, ...). - When handles are pointers to opaque structures, app typically needs to save all of them in a per flow data structure: struct a1 *p1, struct a2 *p2, struct a3 *p3. -This results in increased complexity and size for the app tables, which can be avoided. - When handles are integers generated by the app as opposed of driver, the app can simply use a single index - let's cal it flow_id - and register it as the handle to each of these flow actions. - No more fake tables. - No more worries about the pointer being valid in one address space and not valid in another. There is some handle lookup to be done by the driver, but this is a trivial task, and checking the validity of the handle (input parameter) is the first thing done by any API function, regardless of which handle style is used. [1] http://www.dpdk.org/ml/archives/dev/2017-February/057368.html > -- > Adrien Mazarguil > 6WIND Regards, Cristian
