add reader dist global shuffle

fluid/PaddleCV/image_classification/dist_train/dist_train.py

@@ -80,9 +80,9 @@ def get_device_num():
         device_num = subprocess.check_output(['nvidia-smi', '-L']).decode().count('\n')
     return device_num
 
-def prepare_reader(is_train, pyreader, args):
+def prepare_reader(is_train, pyreader, args, pass_id=0):
     if is_train:
-        reader = train(data_dir=args.data_dir)
+        reader = train(data_dir=args.data_dir, pass_id_as_seed=pass_id)
     else:
         reader = val(data_dir=args.data_dir)
     if is_train:
@@ -262,6 +262,8 @@ def train_parallel(args):
         num_samples = 0
         start_time = time.time()
         batch_id = 1
+        # use pass_id+1 as per pass global shuffle for distributed training
+        prepare_reader(True, train_pyreader, args, pass_id + 1)
         train_pyreader.start()
         while True:
             try:

fluid/PaddleCV/image_classification/reader.py

@@ -130,11 +130,14 @@ def _reader_creator(file_list,
                     shuffle=False,
                     color_jitter=False,
                     rotate=False,
-                    data_dir=DATA_DIR):
+                    data_dir=DATA_DIR,
+                    pass_id_as_seed=0):
     def reader():
         with open(file_list) as flist:
             full_lines = [line.strip() for line in flist]
             if shuffle:
+                if pass_id_as_seed:
+                    np.random.seed(pass_id_as_seed)
                 np.random.shuffle(full_lines)
             if mode == 'train' and os.getenv('PADDLE_TRAINING_ROLE'):
                 # distributed mode if the env var `PADDLE_TRAINING_ROLE` exits
@@ -166,7 +169,7 @@ def _reader_creator(file_list,
     return paddle.reader.xmap_readers(mapper, reader, THREAD, BUF_SIZE)
 
 
-def train(data_dir=DATA_DIR):
+def train(data_dir=DATA_DIR, pass_id_as_seed=0):
     file_list = os.path.join(data_dir, 'train_list.txt')
     return _reader_creator(
         file_list,
@@ -174,7 +177,8 @@ def train(data_dir=DATA_DIR):
         shuffle=True,
         color_jitter=False,
         rotate=False,
-        data_dir=data_dir)
+        data_dir=data_dir,
+        pass_id_as_seed=pass_id_as_seed)
 
 
 def val(data_dir=DATA_DIR):