I hate it when libraries try this sort of thing. I've already used all of the cores higher up in the program logic where it's far more effective, but doing that

I hate it when libraries try this sort of thing. I've already used all of the cores higher up in the program logic where it's far more effective, but doing that all the library is going to achieve is a net slow down of all throughput. Don't blindly throw work at multiple cores low down in algorithms. Amdahl's law tells you that the pay off is likely low, and if the program already makes proper use of the cores you're just going to slow things down.