On 07/01/2016 01:36 PM, Daniel Lezcano wrote:

On 06/30/2016 05:37 PM, Nicolas Pitre wrote:

quoted

On Thu, 30 Jun 2016, Daniel Lezcano wrote:

quoted

+    }

quoted

+}

What bothers me with this division is the benefit of adding an extra
ultra
optimized division by 1000 in cpuidle.h while we have already
ktime_divns
which is optimized in ktime.h.

It is "optimized" but still much heavier than what is presented above as
it provides maximum precision.

It all depends on how important the performance gain from the original
shift by 10 was in the first place.

Actually the original shift was there because it was convenient as a
simple ~div1000 operation. But against all odds, the approximation
introduced a regression on a very specific use case on PowerPC.

We are not in the hot path and I think we can live with a ktime_divns
without problem. That would simplify the fix I believe.

I agree too. I'll post next version with this.

Thanks,
Shreyas