[RFC PATCH v1 0/5] Adjust wording for NUMA vs. socket ID in DPDK

[Morten Brørup]

> From: Anatoly Burakov [mailto:anatoly.burakov at intel.com]
> Sent: Friday, 6 September 2024 13.47
> To: dev at dpdk.org
> Subject: [RFC PATCH v1 0/5] Adjust wording for NUMA vs. socket ID in DPDK
> 
> While initially, DPDK has used the term "socket ID" to refer to physical
> package
> ID, the last time DPDK read "physical_package_id" for socket ID was ~9 years
> ago, so it's been a while since we've actually switched over to using the term
> "socket" to mean "NUMA node".
> 
> This wasn't a problem before, as most systems had one NUMA node per physical
> socket. However, in the last few years, more and more systems have multiple
> NUMA
> nodes per physical CPU socket. Since DPDK used NUMA nodes already, the
> transition was pretty seamless, however now we're faced with a situation when
> most of our documentation still uses outdated terms, and our API is ripe with
> references to "sockets" when in actuality we mean "NUMA nodes". This could be
> a
> source of confusion.
> 
> While completely renaming all of our API's would be a huge effort, will take a
> long time and arguably wouldn't even be worth the API breakages (given that
> this
> mismatch between terminology and reality is implicitly understood by most
> people
> working on DPDK, and so this isn't so much of a problem in practice), we can
> do
> some tweaks around the edges and at least document this unfortunate reality.
> 
> This patchset suggests the following changes:
> 
> - Update rte_socket/rte_lcore documentation to refer to NUMA nodes rather than
> sockets - Rename internal structures' fields to better reflect this intention
> -
> Rename --socket-mem/--socket-limit flags to refer to NUMA rather than sockets
> -
> Add internal API to get physical package ID [1]
> 
> The documentation is updated to refer to new EAL flags, but is otherwise left
> untouched, and instead the entry in "glossary" is amended to indicate that
> when
> DPDK documentation refers to "sockets", it actually means "NUMA ID's". As next
> steps, we could rename all API parameters to refer to NUMA ID rather than
> socket
> ID - this would not break neither API nor ABI, and instead would be a
> documentation change in practice.
> 
> [1] This could be used to group lcores by physical package, see e.g.
> discussion
>     under this patch:
> https://patches.dpdk.org/project/dpdk/cover/20240827151014.201-1-
> vipin.varghese at amd.com/

Thank you for cleaning this up, Anatoly.

I would prefer to take one more step and also rename functions and parameters, e.g. rte_socket_id() -> rte_numa_id().

For backwards compatibility, macros/functions with the old names can be added.