Messages in this thread | | | Subject | Re: [v1,net-next 3/4] net: qos: police action add index for tc flower offloading | From | Jamal Hadi Salim <> | Date | Wed, 24 Jun 2020 08:44:34 -0400 |
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On 2020-06-23 7:52 p.m., Po Liu wrote: > Hi Jamal, > >
>>>> My question: Is this any different from how stats are structured? >>>
[..] >> My question: Why cant you apply the same semantics for the counters? >> Does your hardware have an indexed counter/stats table? If yes then you > > Yes,
That is the point i was trying to get to. Basically: You have a counter table which is referenced by "index" You also have a meter/policer table which is referenced by "index".
For policers, they maintain their own stats. So when i say: tc ... flower ... action police ... index 5 The index referred to is in the policer table
But for other actions, example when i say: tc ... flower ... action drop index 10 The index is in the counter/stats table. It is not exactly "10" in hardware, the driver magically hides it from the user - so it could be hw counter index 1234
The old approach is to assume the classifier (flower in this case) has a counter. The reason for this assumption is older hardware was designed to deal with a single action per match. So a counter to the filter is also the counter to the (single) action. I get the feeling your hardware fits in that space.
Modern use cases have evolved from the ACL single match and action approach. Maintaining the old thought/architecture breaks in two use cases: 1) when you have multiple actions per policy filter. You need counter-per-action for various reasons 2) Sharing of counters across filters and action. This can be achieve
tc supports the above and is sufficient to cover the old use cases. I am just worried, architecturally, we are restricting ourselves to the old scheme.
Another reason this is important is for the sake of analytics. A user space app can poll just for the stats table in hardware (or the cached version in the kernel) and reduce the amount of data crossing to user space..
cheers, jamal
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