def create_blobs_queues(self):
        """Create one BlobsQueue for each GPU to hold mini-batches."""
        for gpu_id in range(self._num_gpus):
            with c2_utils.GpuNameScope(gpu_id):
                workspace.RunOperatorOnce(
                    core.CreateOperator(
                        'CreateBlobsQueue', [], [self._blobs_queue_name],
                        num_blobs=len(self.get_output_names()),
                        capacity=self._blobs_queue_capacity
                    )
                )
        return self.create_enqueue_blobs()
Create one BlobsQueue for each GPU to hold mini-batches.
detectron/roi_data/loader.py