While PSS type simualtion of extracted netlist, it takes a lot of time ( like 12 to 14 hrs). ( IC5141,MMSIM12)
Is there any ways of running things so that the simulations can exploit the Multicores in the machine/workstation.
Do not fill in the process affinity - leave it blank. It's an esoteric option which can potentially give some extra speed, but it has to be used very carefully (the idea is that it allows you to tell the simulator which range of cores you want to "reserve" - the danger is that if you have multiple simulations reserving the same specific core numbers, it can end up being slower, of course). Without this the OS will take care of allocating cores (which may change over time depending on the machine loading).
If you specify the number of threads as "auto", it will pick up to 8 (depending on the machine having that number of cores, and the circuit being large enough to benefit from them). If "manual" you could specify 16 (or whatever number you want).
You should also select "APS" of course.
That's it - very simple.