On Wed, Jan 20, 2016 at 02:17:57PM -0500, Nicolas Pitre wrote: > > It is also a friggin pointless /1000. The cpuidle code also loves to do > > this, and its silly, u64 add/sub are _way_ cheaper than u64 / 1000. > > For the purpose of this code, nanoseconds simply provides too many bits > for what we care. Computing the variance implies squared values. > > *However* we can simply do diff = (timestamp - w->timestamp) >> 10 > instead. No need to have an exact microsecs base.
Right, you could also reduce bits at the variance computation, but yes.
