tree 8433b6c44e9a9602ecce22b829f3f832282b8d1d
parent 49e36753679cc9c5d81e0b55ce26e77a12ba7e06
author A. Unique TensorFlower <gardener@tensorflow.org> 1610058562 -0800
committer TensorFlower Gardener <gardener@tensorflow.org> 1610058854 -0800

PSv2: Shutdown the worker preemption thread in ClusterCoordinator's destructor.

When ClusterCoordinator's destructor is called, mark the worker preemption thread as finished to stop the thread.

Notices the Cluster and Worker objects will not be destroyed due to the threading.Thread object holds a reference to the cluster object.

There will be 2 following CLs to address the Cluster/Worker deletion:
1. Close the worker threads in ClusterCoordinator's destructor.
2. Use weakref as target function for threading.Thread objects, to ensure Cluster/Worker objects can be garbage collected in memory.

PiperOrigin-RevId: 350639066
Change-Id: I23b54912f9b450fb2ccbe6b1da69d2bf5bc55aa5