GPU device selection#
This page describes GPU device selection on a multi-GPU system.
1. Media (VAAPI based) elements#
GStreamer VAAPI plugin supports environment variable
GST_VAAPI_DRM_DEVICE which allows to select GPU device for VAAPI elements (and
decodebin element in case it
internally works on VAAPI elements).
The environment variable GST_VAAPI_DRM_DEVICE expects GPU device driver path,
/dev/dri/renderD128 typically represents first GPU device on system,
/dev/dri/renderD129 represents second GPU device on system, etc.
For example, the following command forces VAAPI elements (and decodebin) to use second GPU device
2. Inference (OpenVINO™ based) elements#
In case of video decode running on CPU and inference running on GPU, the
device property in inference elements allows
to select GPU device according to OpenVINO™ GPU device naming
with devices enumerated as “GPU.0”, “GPU.1”, etc, for example:
gst-launch-1.0 "... ! decodebin force-sw-decoders=true ! gvadetect device=GPU.1 ! ..."
In case of both video decode and inference running on GPU, select GPU device via setting environment variable for VAAPI decode element,
device=GPU for all inference elements. It allows inference elements to query VAAPI context from VAAPI decode element
and automatically run inference and pre-processing on same GPU device as video decode (GPU device affinity).
For example (selecting second GPU device for decode and inference):
export GST_VAAPI_DRM_DEVICE=/dev/dri/renderD129 gst-launch-1.0 "... ! decodebin ! gvadetect device=GPU ! ..."