This is the stack of PRs that supports out or order execution for threaded/async actors. Next PR #20149
At a high level, threaded actor/async actor already don't guarantee execution order, and the current "sequential" order implementation has caused some confusion and inconvenience. Please refer to #19822 for detailed discussion.
The major changes of this stack is
introduce OutOfOrderActorSubmitQueue ([Core][actor out-of-order execution 3/n] Introducing out-of-order actor submit queue #20150)
Specifically, we have a per-client task submit queue, which guarantees the sequential order of task submission. In [Core][actor out-of-order execution 3/n] Introducing out-of-order actor submit queue #20150 we introduce OutOfOrderActorSubmitQueue, which relaxes the guarantee; it send the task over the network as soon as its dependency is resolved.
-- there are 2 PRs ([Core][actor out-of-order execution 1/n] Move CoreWorkerDirectActorTaskSubmitter into a separate file #20148 and [Core][actor out-of-order execution 2/n] create abstraction for the queuing logic on the client/actor submission. #20149) precedes this PR, which refactor the actor submission logic to make the abstraction possible.
OutOfOrderActorSchedullingQueue ([Core][actor out-of-order execution 5/n] implement out-of-order scheduling queue #20176)
Similarly, we also have a per-client task scheduling queue on the actor to ensure tasks are executed according to the submission order (sequence_no). OutOfOrderActorSchedullingQueue relaxes the guarantee by enqueuing the task as soon as all their dependencies are resolved.
-- there is one PR ([Core][actor out-of-order execution 4/n] refactor the actor receiver code #20160) precedes this PR, which refactor the actor scheduling logic to make it the code easier to read; however this one is optional.
plumbing PR ([Core][actor out-of-order execution 6/n] plumbing work to make it work e2e #20177)
This PR enables the out of order execution by introducing options(execute_out_of_order=True); and create actor client/server components according to the configuration.
There are something the PR hasn't touched upon is the restart/retry guarantees, which might need some discussion.
This PR we separate client from server code for Actor task submission. This makes the follow up change easier.
## Why are these changes needed?
This change adds Python publisher and subscriber in `gcs_utils.py`, and GRPC handler on GCS for publishing iva GCS. Error info is migrated to use the GCS-based pubsub, if feature flag `RAY_gcs_grpc_based_pubsub=true`.
Also, add a `--gcs-address` flag to some Python processes. It is not set anywhere yet, but will be set aftering Redis-less bootstrapping work.
Unit tests are added for the Python publisher and subscriber. Migrated error info publishers and subscribers are tested with existing unit tests, e.g. tests calling `ray._private.test_utils.get_error_message()` to ensure error info is published.
GCS based pubsub has gaps in handling deadline, cancelled requests and GCS restarts. So 3 more unit tests are disabled in the `HA GCS` mode. They will be addressed in a separate change.
## Related issue number
* Added imports to Pongv0 example
* Added comment
* Apply suggestions from code review
Co-authored-by: will <will@anyscale.com>
Co-authored-by: Sven Mika <sven@anyscale.io>
## Why are these changes needed?
This is part of redis removal project. In this PR all direct usage of redis got removed except function table.
Function table will be migrated in the next PR
## Related issue number
#19443
