in-kernel PM: support NUMA awareness

[roman-shuhov]

Pre-requisites

• A similar idea has not been reported before.
• mptcp.dev website does not cover my case.
• The wiki doesn't cover my case.

Description

Would be great to have an ability to set NUMA locality for the endpoints, so if process is pinned to specific NUMA node MPTCP connection is only using "local"(from NUMA perspective) entries.

Solution

rought idea is to have new "property" for endpoints, that specify 1 or many supported/allowed NUMA nodes. When MPTCP socket is created, numa locality of current process is recorded and is used later to identify matching endpoints to establish new subflows

Considered alternatives

n/a

Additional context

No response

[matttbe]

Hi @roman-shuhov,

Thank you for sharing this idea!

Some people were interested to change the MPTCP packet scheduler to take the NUMA node in consideration (see here), but doing that on the PM side makes sense (and is easier/cleaner).

As an alternative, would it work for you to have different netns per NUMA node? You can set different endpoints per netns.

[geliangtang]

Hi @roman-shuhov,

Once the MPTCP BPF Path Manager (see: #74) is implemented after some time, you have the option to create a custom NUMA-aware path manager via BPF.

[roman-shuhov]

nice @geliangtang, do you think it's in a good enough shape to try for experimentation?