Memory leak with multiple GPU and BLS.

Description

I have multiple GPUs and a single Triton server's pod running inside Kubernetes cluster with multiple models including BLS and TensorRT's engine models.

When my models are running on node with single GPU there is no issue at all, but adding additional GPU results in slowly increasing memory.

I also observed rapidly increasing memory while using two GPUs, but only on first one (take a look at chart below).

Triton Information

Tested with official images:

nvcr.io/nvidia/tritonserver:23.12-py3
nvcr.io/nvidia/tritonserver:24.04-py3

To Reproduce

My sample bls look like one below:

class TritonPythonModel:
    def __init__(self) -> None:
        self.__bbox_service = BBoxService()
        self.__image_service = ImageService()

    async def execute(self, requests):
        responses = []

        for request in requests:
            image_triton = pb_utils.get_input_tensor_by_name(request, "IMAGES")
            image_tensor = from_dlpack(image_triton.to_dlpack()).cuda().to(torch.float32)  # type: ignore

            image_tensor = self.__image_service.reverse_last_channel(image_tensor)

            preprocessed_image_tensor = self.__preprocess(image_tensor, _PREPROCESS_LETTERBOX_SIZE).to(torch.float16)

            inference_request_input = pb_utils.Tensor.from_dlpack("images", to_dlpack(preprocessed_image_tensor))  # type: ignore
            inference_request = pb_utils.InferenceRequest(  # type: ignore
                model_name="__model:0",
                requested_output_names=["output0"],
                inputs=[inference_request_input],
            )

            inference_response = await inference_request.async_exec()

            prediction_triton = pb_utils.get_output_tensor_by_name(inference_response, name="output0")
            prediction_tensor = from_dlpack(prediction_triton.to_dlpack())  # type: ignore

            bboxes_tensor = self.__postprocess(prediction_tensor, image_tensor.shape, _PREPROCESS_LETTERBOX_SIZE)
            bboxes_tensor = bboxes_tensor.contiguous()

            bboxes_triton = pb_utils.Tensor.from_dlpack("BBOXES", to_dlpack(bboxes_tensor.to(torch.float16)))  # type: ignore
            inference_response = pb_utils.InferenceResponse(output_tensors=[bboxes_triton])  # type: ignore
            responses.append(inference_response)

        return responses

Wondering if those cuda() or device="cuda" used inside my preprocess / image service can raise issues while running on multiple GPUs.

Expected behavior No memory leak and proper requests load balance.

triton-inference-server / server

Memory leak with multiple GPU and BLS. #7190