Single server, one tenant, multiple processes in parallel

I have a deployment where I have a single server, with 2 cores, 5GB RAM. Flowable 6.4.1
It runs 1 tenant, and that tenant has many processes deployed.

If I run a given process alone, it takes about 1 minute.
If I run the same process at the same time, let’s say 10 instances, all process finish in about 12 minutes. All the execution seem to follow some kind of sequential with a slot of time for each one of those.

How can I found out more about how to setup to run those process in parallel.

Here I am not talking about parallel gateway. I am talking about different BPMNs running at the same time for the same tenant.

I would appreciate some clarification. I am reading the documentation, I am thinking it is related to DefaultAsyncJobExecutor and JobService. But I am still not sure.

Thank you