Why do we need to verify runningWorkerCount when submitting a task? about pond HOT 2 CLOSED

Hey @alitto thank you for your reply

We need to check the worker count using the workerCount counter because idleWorkerCount is not as reliable. If we only check whether p.Idle() > 0, then it could happen that we submit a task to the tasks channel right before this line https://github.com/alitto/pond/blob/master/pond.go#L331, where idleWorkerCount is decremented.

If we check runningWorkerCount>0 && p.Idle()>0, it could also happen that we submit a task to the tasks channel right before this line https://github.com/alitto/pond/blob/master/pond.go#L331, where idleWorkerCount is decremented. and at that moment, the runningWorkerCount may be 1, am i right ?

This can cause the task to wait in the tasks channel forever (if no other tasks are submitted afterwards). But i do not know how to prove it.

from pond.

Hey @chengyayu! thank you 🙂
We need to check the worker count using the workerCount counter because idleWorkerCount is not as reliable. If we only check whether p.Idle() > 0, then it could happen that we submit a task to the tasks channel right before this line https://github.com/alitto/pond/blob/master/pond.go#L331, where idleWorkerCount is decremented.
This can cause the task to wait in the tasks channel forever (if no other tasks are submitted afterwards).
workerCount, on the other hand, is updated in a synchronized fashion using a mutex, and that, along with checking the idle counter > 0, guarantees there is at least 1 running goroutine. This goroutine may or may not be really idle, but that's fine because we just need to make sure the task will eventually be picked up.

from pond.