Convert alpha to use clocksource
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From: Thomas Gleixner on 22 Mar 2010 10:30 On Mon, 22 Mar 2010, Johannes Weiner wrote: > > Though, even after a glance over the clocksource code, I've not > > gotten yet to how one could estimate the "shift" value... > > Any hints? > > I had the same problem with xtensa and added a comment about what I > did in there, maybe it helps: > > arch/xtensa/kernel/time.c > > I took the upper bound of the multiplicator (nsecs per counter unit) > and subtracted its logarithm from my available 32 bits. The result > is the highest possible shift value that works for the clocksource. clocks_calc_mult_shift() is what you are looking for. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Johannes Weiner on 22 Mar 2010 12:50
On Mon, Mar 22, 2010 at 03:22:12PM +0100, Thomas Gleixner wrote: > On Mon, 22 Mar 2010, Johannes Weiner wrote: > > > Though, even after a glance over the clocksource code, I've not > > > gotten yet to how one could estimate the "shift" value... > > > Any hints? > > > > I had the same problem with xtensa and added a comment about what I > > did in there, maybe it helps: > > > > arch/xtensa/kernel/time.c > > > > I took the upper bound of the multiplicator (nsecs per counter unit) > > and subtracted its logarithm from my available 32 bits. The result > > is the highest possible shift value that works for the clocksource. > > clocks_calc_mult_shift() is what you are looking for. Oh, thanks! That was not yet around at the time. Hannes -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |