begin voc on gpu3

configs/_base_/datasets/voc0712.py

 # dataset settings
 dataset_type = 'VOCDataset'
-data_root = 'data/VOCdevkit/'
+#data_root = 'data/VOCdevkit/'
+data_root = '/opt/Dataset/VOCdevkit/'
 img_norm_cfg = dict(
     mean=[123.675, 116.28, 103.53], std=[58.395, 57.12, 57.375], to_rgb=True)
 train_pipeline = [