code: def reached_preemption_sync_point(step_id: int) -> bool:
      """Determine whether all hosts have reached a preemption sync step.
  
      When any host receives a preemption notice, the notice is propagated to all
      hosts and triggers a synchronization protocol in the background. The
      synchronization protocol calculates the maximum step ids from all hosts, and
      uses the next step id (i.e., max + 1) as the safe step to save a checkpoint.
      All hosts should continue training more steps until this method returns True,
      indicating that the `step_id` is equal to the safe step and the hosts should
      start saving a checkpoint.
  
      To use this API, all hosts must start training from the same step and call it
      at every training step. Example usage:
  
      ```
      def should_save(step_id: int) -> bool:
  
        # Should save an on-demand checkpoint for preemption
        if multihost_utils.reached_preemption_sync_point(step_id):
          return True
  
        # Should save a regular checkpoint
        return step_id - last_saved_checkpoint_step >= save_interval_steps
      ```
  
      Preemption notice is provided by the cluster scheduler to notify the
      application in advance before it gets evicted. By default, we use SIGTERM as
      the signal for preemption notice.
  
      TODO(b/230630494): Add instructions for customized preemption notice.
  
      Returns:
        A boolean indicating whether all hosts have reached a synchronization step
        after some hosts are preempted.
  
      Raises:
        RuntimeError: if preemption sync manager has not been inititialized.
      """
      if distributed.global_state.client is None:
          return False
      sync_manager = distributed.global_state.preemption_sync_manager
      if sync_manager is None:
          raise RuntimeError(
              "Preemption sync manager has not been initialized."
          )
      return sync_manager.reached_sync_point(step_id)
  
imports: from __future__ import annotations
  from functools import partial, lru_cache
  from typing import Optional
  import zlib
  from typing import Any
  import jax
  import jax.numpy
  from jax.tree_util import tree_flatten, tree_map, tree_unflatten
  from jax._src import core
  from jax._src.interpreters import ad
  from jax._src.interpreters import batching
  from jax._src.interpreters import mlir
  from jax._src import array
  from jax._src import sharding_impls
  from jax._src.interpreters import pxla
  from jax.interpreters import xla
  from jax._src import pjit
  from jax.experimental.pjit import pjit
  from jax.sharding import PartitionSpec
  from jax._src import distributed
  from jax._src.util import safe_zip
  import numpy
label_desc: Use image node_id 8 for calling a global function with example usage: reached_preemption_sync_point(step_id) and returns: sync_manager, False