I'm not sure why or what your changing in the config.xml?
"<cpus v='4'/>, but also tried: <cpus v='0,3,4,7'/> " ? is this a config modification
I limit resources with Docker "Extra Parameters"
Here is mine. "--cpuset-cpus=1 --cpu-shares=2 --cpu-period=100000 --cpu-quota=30000 --cap-add=SYS_NICE --memory="256m" --memory-swap="384m" --log-opt max-size=50m --log-opt max-file=1".
--cpuset-cpus=1 [ sets number of cpus ]
--cpu-shares=2 [ sets weighted priority of container ]
--cpu-period=100000 --cpu-quota=30000 [ limits cpu max usage. this is 30% ]
--memory="256m" --memory-swap="384m" [ limits memory usage ]
--log-opt max-size=50m --log-opt max-file=1" [ controls log file size ]
Here is a good reference. https://docs.docker.com/engine/reference/run/
I'm no expert but hopefully this helps some using this container.