Hi Ori,

-----Original Message-----
From: Ori Kam <redacted>
Sent: Monday, March 29, 2021 10:23 AM
To: Matan Azrad <redacted>; Dumitrescu, Cristian
[off-list ref]; Li Zhang [off-list ref]; Dekel Peled
[off-list ref]; Slava Ovsiienko [off-list ref]; Shahaf
Shuler [off-list ref]; lironh@marvell.com; Singh, Jasvinder
[off-list ref]; NBU-Contact-Thomas Monjalon
[off-list ref]; Yigit, Ferruh [off-list ref]; Andrew
Rybchenko [off-list ref]; Jerin Jacob
[off-list ref]; Hemant Agrawal [off-list ref];
Ajit Khaparde [off-list ref]
Cc: dev@dpdk.org; Raslan Darawsheh <redacted>; Roni Bar Yanai
[off-list ref]
Subject: RE: [PATCH 1/2] [RFC]: ethdev: add pre-defined meter policy API

Hi All,

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-----Original Message-----
From: Matan Azrad <redacted>
Subject: RE: [PATCH 1/2] [RFC]: ethdev: add pre-defined meter policy API

Hi Cristian

Thank you for your important review!
I agree with all your comments except one, please see inline.

From: Dumitrescu, Cristian

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Hi Li and Matan,

Thank you for your proposal, some comments below.

I am also adding Jerin and Hemant to this thread, as they also participated

in

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the definition of the rte_mtr API in 2017. Also Ajit expressed some

interest in

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a

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previous email.

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-----Original Message-----
From: Li Zhang <redacted>
Sent: Thursday, March 18, 2021 8:58 AM
To: dekelp@nvidia.com; orika@nvidia.com; viacheslavo@nvidia.com;
matan@nvidia.com; shahafs@nvidia.com; lironh@marvell.com; Singh,
Jasvinder [off-list ref]; Thomas Monjalon
[off-list ref]; Yigit, Ferruh [off-list ref];

Andrew

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Rybchenko [off-list ref]; Dumitrescu, Cristian
[off-list ref]
Cc: dev@dpdk.org; rasland@nvidia.com; roniba@nvidia.com
Subject: [PATCH 1/2] [RFC]: ethdev: add pre-defined meter policy API

Currently, the flow meter policy does not support multiple actions per
color; also the allowed action types per color are very limited.
In addition, the policy cannot be pre-defined.

Due to the growing in flow actions offload abilities there is a
potential for the user to use variety of actions per color differently.
This new meter policy API comes to allow this potential in the most
ethdev common way using rte_flow action definition.
A list of rte_flow actions will be provided by the user per color in
order to create a meter policy.
In addition, the API forces to pre-define the policy before the meters
creation in order to allow sharing of single policy with multiple
meters efficiently.

meter_policy_id is added into struct rte_mtr_params.
So that it can get the policy during the meters creation.

Policy id 0 is default policy. Action per color as below:
green - no action, yellow - no action, red - drop

Allow coloring the packet using a new rte_flow_action_color as could
be done by the old policy API,

The proposal essentially is to define the meter policy based on rte_flow

actions

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rather than a reduced action set defined specifically just for meter object.

This

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makes sense to me.

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The next API function were added:
- rte_mtr_meter_policy_add
- rte_mtr_meter_policy_delete
- rte_mtr_meter_policy_update
- rte_mtr_meter_policy_validate
The next struct was changed:
- rte_mtr_params
- rte_mtr_capabilities
The next API was deleted:
- rte_mtr_policer_actions_update

Signed-off-by: Li Zhang <redacted>
---
 lib/librte_ethdev/rte_flow.h       |  18 ++++
 lib/librte_ethdev/rte_mtr.c        |  55 ++++++++--
 lib/librte_ethdev/rte_mtr.h        | 166 ++++++++++++++++++++---------
 lib/librte_ethdev/rte_mtr_driver.h |  45 ++++++--
 4 files changed, 210 insertions(+), 74 deletions(-)

diff --git a/lib/librte_ethdev/rte_flow.h

b/lib/librte_ethdev/rte_flow.h index 669e677e91..5f38aa7fa4 100644

--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h

@@ -31,6 +31,7 @@
 #include <rte_ecpri.h>
 #include <rte_mbuf.h>
 #include <rte_mbuf_dyn.h>
+#include <rte_meter.h>

 #ifdef __cplusplus
 extern "C" {

@@ -2236,6 +2237,13 @@ enum rte_flow_action_type {
       * See struct rte_flow_action_modify_field.
       */
      RTE_FLOW_ACTION_TYPE_MODIFY_FIELD,
+
+     /**
+      * Color the packet to reflect the meter color result.
+      *
+      * See struct rte_flow_action_color.
+      */
+     RTE_FLOW_ACTION_TYPE_COlOR,

Typo here, it should be RTE_FLOW_ACTION_TYPE_COLOR.

Why do we need this action?

We need this new proposed RTE_FLOW_ACTION_TYPE_COLOR action to set the packet color in the packet mbuf (i.e. in the mbuf::sched:color field) in order to tell the later stages of the pipeline what the packet color is.

if it is to save the color it should be done by using mark/metadata

As stated in its description, the  RTE_FLOW_ACTION_TYPE_MARK action Is setting the mbuf::hash.fdir.hi field, which is used for a different purpose that is unrelated to the packet color, which has its own field within the mbuf.

Or by the action of meter.

The new proposed RTE_FLOW_ACTION_TYPE_COLOR action is indeed an action of the meter and meter only, right?

For example you can see

RTE_FLOW_ACTION_TYPE_SECURITY
Which if exist saves the session id to a dedicated mbuf field.

The meter processing and action take place independently of the security API: it can be enabled when the security API is disabled and is not conditioned in any way by the security API. To be honest, I don't understand the connection with the security API that you are trying to make here.

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 };

 /**

[Snip]

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I suggest you do not redundantly specify the value of the default policy ID

in

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the

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comment. Replace by "Default policy ID."

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+ * Action per color as below:
+ * green - no action, yellow - no action, red - drop

This does not make sense to me as the default policy. The default policy

should

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be "no change", i.e. green -> green (no change), yellow -> yellow (no

change),

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red -> red (no change).

Can you explain why it doesn't make sense to you?

Meter with "no change" for all colors has no effect on the packets so it is
redundant action which just costs performance and resources - probably

never

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be used.

The most common usage for meter is to drop all the packets come above

the

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defined rate limit - so it makes sense to take this behavior as default.

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I suggest we avoid the "no action" statement, as it might be confusing.

Maybe "do nothing" is better?

Maybe passthrough? Or in rte_flow passthru

No, we need to save the packet color in the packet mbuf (mbuf::sched:color), and the RTE_FLOW_ACTION_TYPE_PASSTHRU action is not doing this.

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+ * It can be used without creating it by the rte_mtr_meter_policy_add
function.
+ */

Best,
Ori

Regards,
Cristian