I'm planning to run for example 10 instances of a single software - single-threaded game server. They will run on a server machine(not VPS) on plain Linux Ubuntu(console version).
My question is, if I do this, all the load will be on the main thread? or each instance will take his own thread.
A thread always belongs to a process, so if you have 10 instances of a software running on 10 processes they will run on the main thread of each process. Then the processor will assign each thread to an specific core depending on the available resources