mmdetection/configs/gcnet/mask-rcnn_r50-syncbn-gcb-r4-c3-c5_fpn_1x_coco.py

_base_ = '../mask_rcnn/mask-rcnn_r50_fpn_1x_coco.py'
model = dict(
    backbone=dict(
        norm_cfg=dict(type='SyncBN', requires_grad=True),
        norm_eval=False,
        plugins=[
            dict(
                cfg=dict(type='ContextBlock', ratio=1. / 4),
                stages=(False, True, True, True),
                position='after_conv3')
        ]))