From: Varghese, Vipin [mailto:vipin.vargh...@amd.com]
Sent: Monday, 3 March 2025 10.06
[Public]
Hi Morten,
snipped
From: Thomas Monjalon [mailto:tho...@monjalon.net]
Sent: Thursday, 13 February 2025 09.34
13/02/2025 04:09, Varghese, Vipin:
[AMD Official Use Only - AMD Internal Distribution Only]
Adding Thomas and Ajit to the loop.
Hi Ajit, we have been using the patch series for identifying the
topology and getting l3 cache id for populating the steering tag
for
Device Specific Model & MSI-x driven af-xdp for the experimental
STAG
firmware on Thor.
Excellent. A real life example use case helps the review process a
lot!
Steering tag is one of the examples or uses, as shared in the current
patch series we make use of these for other examples too.
Eventdev, pkt-distributor and graph nodes are also in works to exploit
L2|L3 cache local coherency too.
Hence current use of topology library helps in 1. workload
placement
in same Cache or IO domain 2. populating id for MSIx or Device
specific model for steering tags.
Thomas and Ajith can we get some help to get this mainline too?
Yes, sorry the review discussions did not start.
It has been forgotten.
I think the topology/domain API in the EAL should be co-designed with
the steering
tag API in the ethdev library, so the design can be
reviewed/discussed in its entirety.
As shared in the discussion, we have been exploring simplified approach
for steering tags, namely
1. pci-dev args (crude way)
2. flow api for RX (experimental way)
Based on the platform (in case of AMD EPYC, these are translated to `L3
id + 1`)
We do agree rte_ethdev library can use topology API. Current topology
API are designed to be made independent from steering tags, as other
examples do make use of the same.
To help the review discussion, please consider describing the
following:
Which APIs are for slow path, and which are for fast path?
Which APIs are "must have", i.e. core to making it work at all, and
which APIs are
"nice to have", i.e. support APIs to ease use of the new features?
Yes, will try to do the same in updated version. For Slow and Fast path
API I might need some help, as I was under the impression current
behavior is same rte_lcore (invoked at setup and before remote launch).
But will check again.
