On Fri, Dec 04, 2015 at 09:51:02AM -0800, Jacob Pan wrote: > On Fri, 4 Dec 2015 09:22:56 +0100 > Peter Zijlstra <[email protected]> wrote: > > > Also, yuck @ powercap/intel_rapl.c for doing rdmsr_on_cpu() + > > wrmsr_on_cpu() all over the place. > Can you please be more specific? is the concern related to the > overhead of IPI? I am doing these calls based on MSR CPU scope and > consider the fact that access is less frequent.
Yeah, its just offensive to do an IPI to read a value, then twiddle a few bits on the value and then IPI again to store the value. I know its low freq, and that MSR access is slow, but *groan*. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
