Erlang on openstack VM with numa awareness

[Satish Patel]

Hi,

I am trying to run erlang application on openstack vm and getting very
poor performance and after testing i found something going on with
NUMA, This is what i observe in my test.

My openstack compute host with 32 core so i have created 30 vCPU core
vm on it which has all NUMA awareness, when i am running Erlang
application benchmark on this VM getting worst performance but then i
create new VM with 16 vCPU core (In this case my all VM cpu pinned
with Numa-0 node) and in this case benchmark result was great.

based on above test its clear if i keep VM on single numa node then
performance is much better but when i spread it out to multiple numa
zone it get worse.

But interesting thing is when i run same erlang application run on
bare metal then performance is really good, so trying to understand
why same application running on VM doesn't perform well?

Is there any setting in erlang to better fit with NUMA when running on
virtual machine?