docstring for `distribute_reduction_method` is more specific on when it is needed
@@ -934,6 +934,12 @@ class Model(base_layer.Layer, version_utils.ModelVersionSelector):
"""Settable attribute indicating how the model should reduce
loss and metric values from replicas.
+ By default, tf.distribute takes care of proper synchronization
+ so that "first" is sufficient. If you implement a custom `train_step`
+ as described in [distributed training guide](
+ https://www.tensorflow.org/guide/distributed_training#use_tfdistributestrategy_with_custom_training_loops)
+ you should set this property to `"sum"`.
+
Default: 'first', which will get the value from the first replica.
"""
return self._distribute_reduction_method or "first"
