How to use multiple CPU cores for ROS Gazebo SITL

I want to do a large scale swarm simulation. Even though I set real time factor = 1 in the Gazebo world file, the real time factor is quite low. Obviously, the SITL only uses 1 physical core (2 logical cores). Is it possible to use multiple CPU cores?

@robin-shaun You need to be running multiple instances of px4 sitl to simulate swarms. How are you running multiple instances of SITL?

Have you checked this document?

I succeeded in running multiple instances of SITL and I don’t know why document says
It can only simulate a single type of vehicle at a time
The only problem for me is that the simulation speed is too low.

I want to speed up my gazebo simulation, so I’m going to buy a new PC just for that. So, what should I remember? So far, here’s what I’ve discovered: Make use of a graphics card that has an OpenGL 3D accelerated driver. Use CUDA with parallel-quickstep as directed by:

BUT, I couldn’t find anything about gazebo and multithreading? Is it supported by gazebo simulator? Will a quad-core processor accelerate my simulation, or is it primarily a graphic card issue?