Can someone explain pmset gpuswitch

Checking pmset using terminal, `pmset -g`, I see `gpuswitch` with a default value of `2` on a Mac Pro late 2013. I haven't been able to find documentation for this setting anywhere within the man pages or online. I see most settings posted online are, by default, `gpuswitch 2`. I would expect `0` to disable it, but without any docs, I am unsure. I think it's also possible this setting has no effect on my machine, but I would rather disable it to be sure.