How to do VOSK performance improvements using Gpu ?

Hi

I am trying to use gpu to get good performance.
Using [vosk-model-en-us-0.22-lgraph](https://alphacephei.com/vosk/models/vosk-model-en-us-0.22-lgraph.zip) , we could only manage to run 8 recognizers before reaching 100% cpu. However my requirement is to run atleast 20 to 40 recognizers.
My VM is CentOS (VMware) with 16GB ram, 8 cores and VMware SVGA II Adapter. Currently my hardware improvements is not possible, so I am trying find the other routes to get best performance.

I have tried a brute force method of adding delaying after sending "N" audio packets. This method reduced cpu usage and helped to run 10 recognizers. But this is not sufficient.

I read an article about usage of gpu in vosk https://hub.docker.com/r/alphacep/kaldi-en-gpu. But I got below error.

>docker` run --gpus all -p 2700:2700 alphacep/kaldi-en-gpu
>docker: Error response from daemon: could not select device driver "" with capabilities: `[[gpu]].

Also I am not finding a proper document which can help me read more about it.
So please help me with more details of vosk gpu , requirements and limitations.