wasmtime / PR #12357 [async] Give more priority to high-p... · git-wasmtime

Stream: git-wasmtime

Topic: wasmtime / PR #12357 [async] Give more priority to high-p...

Wasmtime GitHub notifications bot (Jan 15 2026 at 11:33):

TartanLlama opened PR #12357 from TartanLlama:sy/high-priority-queue to bytecodealliance:main:

Currently, the main async event loop processes either all of the high-priority work items, or all of the low-priority work items if there are no high-priority items. This means that, if there are multiple low-priority tasks and an early one adds a task to the high-priority queue, this new task has to wait for the remaining low-priority tasks to complete before it gets a chance to run.

This PR changes the event loop to run at most one low-priority task on every iteration. As such, if this task enqueues a high-priority task, that task will get a chance to run before any other low-priority tasks.

I also reduced the nesting of the poll_until loop and added better names to make the code more easily understandable.

Wasmtime GitHub notifications bot (Jan 15 2026 at 11:33):

TartanLlama requested alexcrichton for a review on PR #12357.

Wasmtime GitHub notifications bot (Jan 15 2026 at 11:33):

TartanLlama requested wasmtime-core-reviewers for a review on PR #12357.

Wasmtime GitHub notifications bot (Jan 15 2026 at 11:34):

TartanLlama edited PR #12357:

Currently, the main async event loop processes either all of the high-priority work items, or all of the low-priority work items if there are no high-priority items. This means that, if there are multiple low-priority tasks and an early one adds a task to the high-priority queue, this new task has to wait for the remaining low-priority tasks to complete before it gets a chance to run.

This PR changes the event loop to run at most one low-priority task on every iteration. As such, if this task enqueues a high-priority task, that task will get a chance to run before any other low-priority tasks.

I also reduced the nesting of the poll_until loop, factored out pulling the work items out of ConcurrentState, and added better names to make the code more easily understandable.