On 04/03/2015 11:37 AM, Linus Torvalds wrote: > On Fri, Apr 3, 2015 at 11:35 AM, H. Peter Anvin <h...@zytor.com> wrote: >> >> For the record, I actually measured the impact of the jump-to-jump when >> I wrote it. It has a small, *but measurable*, positive impact. > > What did you compare against, and how did you measure that? I don't > see how it could *possibly* be faster than just a simple aligned "push > + jmp". >
I wish I remembered the exact details; it took a fair bit of gathering numbers as the spread was quite a bit wider than the delta, but in the end there were two distribution peaks clearly offset. I seem to remember it involving a loop running RDTSC continuously and another RDTSC in the interrupt path. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/