> > Yes. But 150-200 clock cycles are nothing compared to the cache misses > > you get from preemption, so I'd ignore that. Saving 300 clock cycles on > > userspace exits from TR+GSBASE would be about 5% on my Haswell. > > That's still 5% :) Yes, 5% on userspace exits is good (though they're rare). OTOH, 300 clock cycles on preemption are nothing to write home about. Paolo
