On 9/22/22 13:06, Ori Kam wrote:
Hi Andrew,
-----Original Message-----
From: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>
Sent: Thursday, 22 September 2022 10:39
On 9/21/22 15:51, Morten Brørup wrote:
From: Ori Kam [mailto:or...@nvidia.com]
Sent: Wednesday, 21 September 2022 14.41
From: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>
On 9/21/22 12:40, Thomas Monjalon wrote:
21/09/2022 11:04, Ivan Malov:
Now it's clear to me that your intention is to match on exact
ports,
as usual, but this time with a hint for the flow table. Got it.
In your response, you say that matching on ALL vports is not what
the use case needs. OK, I understood. But please note that the
item name does not say "ALL", it says "ANY".
OK. Say, "ANY" is also confusing. Let's then name it "VPORTS_ONLY"
and "PHY_PORTS_ONLY". This way, if user provides item
VPORTS_ONLY
and then provides item REPRESENTED_PORT, these two items do not
contradict each other. Item VPORTS_ONLY defines the scope of some
kind, then the following item, REPRESENTED_PORT, makes it
narrower.
And, in documentation, one can say clearly that the user *may*
omit item VPORTS_ONLY in the exact rule pattern provided that
they have already submitted this item as part of the template.
I think the problem that Rongwei & Ori are trying to solve
is to allocate resources for the templates table in the right
place.
A table can have multiple templates.
If all rules/templates for this table are dedicated to virtual
ports,
then the table will be allocated in a place managing only virtual
ports.
This allocation decision must be taken at table creation,
whereas rules will be created later.
In order to do this specific table allocation for vports,
we need to restrict all templates of the table to be "vports only".
I hope it makes things clearer.
Now the question is how to achieve this? Solutions are:
1/ give a hint to the table allocation
2/ insert a pattern item in all templates of the table
I don't see any other solution. Please propose if there are more
options.
See my mail
3/ use jump rule which ensures that all traffic meets out
expectations
It means that the table creation could be postponed. Or the
table could be per-configured at the point of creation and
finalized when we know that all traffic will be from wires
or from vports. Yes, it complicates internals to achieve
the optimization.
Sorry Andrew your suggestion is not a valid one for the following
reasons:
1. table creation can't be postponed this is a key idea of the rte_flow
template API.
I guess nobody cares if it delays insertion on the first rule
only. Anyway, see below.
2. we can never know what rules will be inserted if the application
doesn't tell us.
how can we know this is the last rule? What do we do with the
first rule?
3. I don't see how jumping helps since it worsens the issue when you
jump to a table,
how does the PMD know if this table should have only wire or only
vports?
Jump rules say so. PMD can analyze there rules.
May be just need an attribute saying that all jump rules
to the table are configured and further attempts to reconfigure
will be rejected?
The idea is the PMD will not analyze rules. That is why we have the table
and template.
Sorry, I don't understand what attribute can be in jump? The jump is just
to table. It can't say anything about the table destination table.
This is all this patch adds the attribute to a table to say where this
table should be located.
I agree with Thomas, there are two valid options, I vote for the hint
since this is the
feature idea to tell the PMD where this resource should be allocated.
This is an optimization; I agree with Ori that a hint is appropriate, like the
MBUF_FAST_FREE hint on TX queues.
No need to add more complexity by requiring the driver to recognize that
the pattern is present in all templates. (And perhaps also remove that
pattern when applying the templates.)
What does the part of the matching criteria so special
that it is allowed to have dedicated hint attribute?
May be we can have really generic solution when any
part of the matching criteria could provide such hints?
That is the point I keep returning to, it is not matching!
This is on which HW resource the table should be allocated.
Sorry, but it is just your HW details that you have different
location/resources for rules which apply on packets coming
from wire and coming from host (vports).
Think about ingress/egress/transfer why are they not in the pattern?
We have no ingress/egress in transfer domain any more because
it is ambiguous.
Transfer itself is really a different domain. Logically and
from privileges point of view. That's why it is important to
distinguish it.
Ingress and egress in non-transfer case are natively bound
to two main functions of the driver: transmit (egress rules)
and receive (ingress rules). In general, it is a matching
criteria as well, but because of its nature (explained
above) it is simply handy to distinguish it from the very
beginning.
They are where rules should be offloaded, they are different domain.
We have just two domains: transfer and non-transfer.
Like we have elsewhere for example in action create we can state on which
domain the action should be created. If the application selects a number of
domains
it may mean that extra resources will be allocated.>
Two more points:
1/ If it is just a hint, it is optional for PMD to
support/handle it. It means that it MUST NOT impose any
limitations on matching. If so, if you want a rule to
be applied on packets coming from wire, you still MUST
specify it in the pattern.
So, it does not sound like a hint in your case.
2/ struct rte_flow_attr is used for really all rules.
How a new attribute should be interpreted in non-transfer
rules? Similar to ingress/egress? Duplication?
Or even harder (if it is NOT a hint): should it really
enforce matching of packets coming from wire (i.e. not
a different vport)? Not sure that it is doable or even
make sense.
We can say that the attribute may be used for the transfer
rules only. If so, it MUST be checked on ethdev level
since it is a generic rule.
3/ struct rte_flow_attr is used for sync and async rules.
As I understand you're using it for async rules only.
Does it make sense for sync rules?
