!2634 Avoid extra recording of summary when end called

Merge pull request !2634 from LiHongzhang/no_step_zero

mindspore/train/callback/_summary_collector.py

@@ -308,6 +308,8 @@ class SummaryCollector(Callback):
         else:
             self._collect_eval_lineage(cb_params)
 
+        # This is a workaround to avoid record '_summary_tensor_cache'.
+        self._record.set_mode('eval')
         # There's nothing special about setting step to 0 here, just to satisfy the interface call
         self._record.record(step=0)
 

mindspore/train/summary/_writer_pool.py

@@ -59,7 +59,7 @@ class WriterPool(Process):
     def run(self):
         writers = self._get_writers()
 
-        with Pool() as pool:
+        with Pool(min(cpu_count(), 32)) as pool:
             deq = deque()
             while True:
                 while deq and deq[0].ready():

mindspore/train/summary/summary_record.py

@@ -202,6 +202,9 @@ class SummaryRecord:
             if not isinstance(value, Tensor):
                 raise TypeError(f'Expect the value to be Tensor, but got {type(value).__name__}')
             np_value = _check_to_numpy(plugin, value)
+            if name in {item['tag'] for item in self._data_pool[plugin]}:
+                entry = repr(f'{name}/{plugin}')
+                logger.warning(f'{entry} has duplicate values. Only the newest one will be recorded.')
             self._data_pool[plugin].append(dict(tag=name, mode=self._mode, value=np_value))
 
         elif plugin in ('train_lineage', 'eval_lineage', 'dataset_graph', 'custom_lineage_data'):