.. _video-cards:

Multiple Video Cards Usage
========================================


Should you have several video cards installed on a physical server, you can create additional ``findface-extraction-api-gpu`` or ``findface-video-worker-gpu`` instances and distribute them across the video cards, one instance per card.  

.. rubric:: In this section:

.. contents::
   :local:

Distribute ``findface-extraction-api-gpu`` Instances Across Several Video Cards 
-----------------------------------------------------------------------------------

To distribute ``findface-extraction-api-gpu`` instances across several video cards, do the following:

#. Stop the initial ``findface-extraction-api-gpu`` service.

   .. code::

      sudo service findface-extraction-api stop

#. Create several copies of the ``/etc/findface-extraction-api.ini`` configuration file, subject to how many video cards you are going to use for feature vector extraction. Append the appropriate GPU device numbers to the new configuration files names as shown in the example below (GPU devices #0 and #6).

   .. code::

      /etc/findface-extraction-api@0.ini
      /etc/findface-extraction-api@6.ini

#. Open the new configuration files. Specify the GPU device numbers and adjust the listening ports.

   .. code::

      sudo vi /etc/findface-extraction-api@0.ini

      listen: 127.0.0.1:18666
      ...

      gpu_device: 0
      ...


   .. code::

      sudo vi /etc/findface-extraction-api@6.ini

      listen: 127.0.0.1:18667
      ...

      gpu_device: 6
      ...

#. Start the new services.

   .. code::

      sudo service findface-extraction-api@0 start
      sudo service findface-extraction-api@6 start


Allocate ``findface-video-worker-gpu`` to Additional Video Card
-----------------------------------------------------------------------------

To create an additional ``findface-video-worker-gpu`` instance and allocate it to a different video card, do the following:
 

#. Display the status of the ``findface-video-worker-gpu`` primary service by executing:

   .. code::

      sudo systemctl status findface-video-worker-gpu.service
      
#. Find the full path to the service in the following line:

   .. code::

      Loaded: loaded (/usr/lib/systemd/system/findface-video-worker-gpu.service); enabled; vendor preset: enabled

   It is ``findface-video-worker-gpu.service`` in our example (name may vary). Create a copy of the service under a new name. 

   .. code::

      sudo cp /usr/lib/systemd/system/findface-video-worker-gpu.service /usr/lib/systemd/system/findface-video-worker-gpu2.service`

#. In the same manner, create a copy of the primary service configuration file under a new name.

   .. code::

      sudo cp /etc/findface-video-worker-gpu.ini /etc/findface-video-worker-gpu2.ini

#. Open the just created configuration file and actualize the GPU device number to use. Modify the streamer port number by the following formula: ``18999 (port number for GPU #0) - GPU device number``, i.e. for the GPU #1, ``port = 18998``, for the GPU #2, ``port = 18997``, and so on.  

   .. code::

      sudo vi /etc/findface-video-worker-gpu2.ini

      ## cuda device number
      device_number = 1

      ...

      #------------------------------      
      [streamer]
      #------------------------------
      ## streamer/shots webserver port, 0=disabled
      ## type:number env:CFG_STREAMER_PORT longopt:--streamer-port
      port = 18999
      ...

#. Open the new service and specify the just created configuration file. 

   .. code::

      sudo vi /usr/lib/systemd/system/findface-video-worker-gpu2.service

      ExecStart=/usr/bin/findface-video-worker-gpu --config /etc/findface-video-worker-gpu2.ini

#. Reload the ``systemd`` daemon to apply the changes. 
 
   .. code::

      sudo systemctl daemon-reload 

#. Enable the new service autostart.

   .. code::

      sudo systemctl enable findface-video-worker-gpu2.service

      Created symlink from /etc/systemd/system/multi-user.target.wants/findface-video-worker-gpu2.service to /usr/lib/systemd/system/findface-video-worker-gpu2.service

#. Launch the new service. 

   .. code::

      sudo systemctl start findface-video-worker-gpu2.service

#. Check the both ``findface-video-worker-gpu`` services status.

   .. code::

      sudo systemctl status findface-video-worker-* | grep -i 'Active:' -B 3 

      ● findface-video-worker-gpu2.service - findface-video-worker-gpu daemon
        Loaded: loaded (/usr/lib/systemd/system/findface-video-worker-gpu2.service; enabled; vendor preset: enabled)
        Active: active (running) since Thu 2019-07-18 10:32:02 MSK; 1min 11s ago

      ...

      ● findface-video-worker-gpu.service - findface-video-worker-gpu daemon
        Loaded: loaded (/usr/lib/systemd/system/findface-video-worker-gpu.service; enabled; vendor preset: enabled)
        Active: active (running) since Mon 2019-07-15 15:18:33 MSK; 2 days ago