OpenSHMEM Sessions (ctx hints) API

davidozog commented 2 years ago

This is a continuation of the Bundles proposal, so closes the #481 pull request. Sessions are a generalization of Bundles, so users can pass hints for context optimization that go beyond just chaining/bundling. There is more discussion on this API design in the original ticket, #189.

As usual, I appreciate any feedback - thanks in advance!

davidozog commented 2 years ago

Also, for those interested, an example of a bare-minimum implementation of this proposed API in Sandia OpenSHMEM here: https://github.com/Sandia-OpenSHMEM/SOS/pull/1065

It simply ignores all hints...

davidozog commented 1 year ago

I address some key suggestions from the unofficial reading on Sept. 30th with commit https://github.com/openshmem-org/specification/pull/493/commits/93f510e33d3158619fc7687bed8b7bb46c26e86d. Thanks for the feedback!

Here are a few other notes from that meeting:

There was another request for an interface to provide values to hints, such as the number of upcoming (chainable) RMA operations. Something like an "epoch" sub-session or a "get/set" API for existing library constants. This was suggested by Brandon Potter at AMD (but don't know his Github handle... does @khamidouche?). Thoughts?
Concern was raised that some implementations will not be able to support sufficiently long chains ("postlists") to see any benefit from the chaining hint in sessions. Did I capture that correctly @manjugv / @naveen-rn?

If anybody feels I missed something, please let me know! I unfortunately lost my PDF notes in a laptop crash, so I'm going by memory...

davidozog commented 7 months ago

~~Special ballot diff: 6417925..6d0f714~~

(cancelled)

davidozog commented 4 months ago

Special ballot diff: aa84edeb..e22a3f15

openshmem-org / specification

OpenSHMEM Sessions (ctx hints) API #493