Comment 10 for bug 1547463

I can confirm it worked back then and still works for me with systemd controls.
That is also what the tests were based on which were good in that regard.

I retested today just to the extend of seeing the options where they should be:
# Xenial guest to test on
$ uvt-kvm create --password=ubuntu --memory 3096 xenial-dpdk-test release=xenial arch=amd64 label=daily
# further commands in the guest
$ sudo apt install openvswitch-switch-dpdk
# Of course this won't work, but we want to test args passed
$ echo "DPDK_OPTS='--dpdk -c test -n 4 -m bugno 1547463'" | sudo tee -a /etc/default/openvswitch-switch
# set the dpdk enabled version
$ update-alternatives --set ovs-vswitchd /usr/lib/openvswitch-switch-dpdk/ovs-vswitchd-dpdk
$ sudo systemctl restart openvswitch-switch
# This triggers the other components and in openvswitch-nonetwork.service the env file is read and all works.
# Of course this give me an "invalid core mask" as test isn't good.
# Switching to the suggested defaults of "--dpdk -c 0x1 -n 4" gets me further

So TL;DR it works for me, maybe the sysV call is broken but honestly I don't mind - far more important is to no more use the old experimental version.

Thereby I set the remaining bug to incomplete and would ask (if still import and and not able or willing to follow to a newer version) how you restart the service - is it the sysV style call that doesn't work for you or something else?