[RFC] ethdev: add template table insertion and matching types
Thomas Monjalon
thomas at monjalon.net
Wed Jan 18 09:50:47 CET 2023
14/12/2022 03:21, Alexander Kozyrev:
> Bring more flexibility and control over both flow rule insertion
> and packet matching mechanisms. Introduce 2 new flow table types:
>
> 1. Allow a user to specify the insertion type used in template tables.
> The insertion type is responsible for choosing the appropriate key
> value used to map inserted flow rules into a template table.
>
> Flow rules can be inserted by calculating the hash value for
> the pattern or inserted by index via the new create_by_index() API.
> The idea of the index-based insertion is to avoid additional matches
> and simply execute predefined actions after jumping to the index.
I don't understand the idea.
Why is it avoiding additional matches?
> The insertion to an already existing index is undefined and
Why is it undefined?
> depends on PMD implementation. An old rule must be destroyed first.
> The index cannot be bigger than the size of the table.
>
> 2. Allow a user to specify the hash calculation function used in template
> tables. The hash calculation type is responsible for the calculation of
> the flow rule index a packet would hit upon arrival at the table.
>
> Control over this is useful for applications with custom RSS algorithms,
> for example. An application can select various packet fields to serve as
> a hash calculation source and jump to the appropriate flow rule location.
> The RSS hash result will be used as the index in the table. For the linear
> hash function, the mapping is one-to-one and the hash result is the index.
> For other hash functions, the index is the hash result module table size.
> The RSS hash result can be retrieved via modify_field API: HASH_RESULT.
>
> Signed-off-by: Alexander Kozyrev <akozyrev at nvidia.com>
> ---
> doc/guides/prog_guide/rte_flow.rst | 20 +++++++
> lib/ethdev/rte_flow.c | 24 ++++++++
> lib/ethdev/rte_flow.h | 96 ++++++++++++++++++++++++++++++
> lib/ethdev/rte_flow_driver.h | 11 ++++
> lib/ethdev/version.map | 3 +
> 5 files changed, 154 insertions(+)
Is there a PMD implementation available on the mailing list?
This is required to accept a new API.
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