On Thu, Feb 12, 2015 at 12:04:54PM +0200, Adrian Hunter wrote: > On 11/02/15 18:12, Peter Zijlstra wrote: > > > > How about something like the below? I _think_ it should mostly work for > > x86, where the tsc is a 64bit wide cycle counter. > > It would have to be based on CLOCK_MONOTONIC_RAW not CLOCK_MONOTONIC Why? > and you would have to check the clocksource is TSC. It implicitly does that; it has that sched_clock_stable() thing, but yeah I suppose someone could change the clocksource even though the tsc is stable. Not using TSC when its available is quite crazy though.. but sure. > Why is CLOCK_MONOTONIC preferred anyway - I would have thought any > adjustment would skew performance timings? Because you can do inter-machine stuff with MONOTONIC and that's entirely impossible with MONO_RAW. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
