On Wed, 2007-05-30 at 19:16 +0200, Peter Zijlstra wrote: > > >From the architecture perspective there are two low level clock hooks to > > implement one is sched_clock() , and at least one clocksource structure. > > Both do essentially the same thing. With timekeepings clocksource > > structure actually being easier to implement cause the math is built in. > > I think you are mistaken here; the two are similar but not identical. > > I see sched_clock() as fast first, accurate second. Whereas the > clocksource thing is accurate first, fast second.
This is true .. However, if there is a speed different it's small. In the past I've replace sched_clock() with a clocksource, and there was no noticeable speed different .. Just recently I replaced x86's sched_clock() math with the clocksource math with no noticable difference .. At least not from my benchmarks .. > There is room for both of them. There is room, but we don't need sched_clock() .. Certainly we shouldn't force architectures to implement sched_clock() by calling it a "bug" if it's lowres. Daniel - 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/
