Rasmus Villemoes 7024b18ca4 cpuidle: menu: avoid expensive square root computation ... Computing the integer square root is a rather expensive operation, at least compared to doing a 64x64 -> 64 multiply (avg*avg) and, on 64 bit platforms, doing an extra comparison to a constant (variance <= U64_MAX/36). On 64 bit platforms, this does mean that we add a restriction on the range of the variance where we end up using the estimate (since previously the stddev <= ULONG_MAX was a tautology), but on the other hand, we extend the range quite substantially on 32 bit platforms - in both cases, we now allow standard deviations up to 715 seconds, which is for example guaranteed if all observations are less than 1430 seconds. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>		2016-02-17 00:27:16 +01:00
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ladder.c	cpuidle: Default to ladder governor on ticking systems	2016-01-15 22:36:19 +01:00
Makefile	cpuidle: consolidate 2.6.22 cpuidle branch into one patch	2007-10-10 00:12:41 -04:00
menu.c	cpuidle: menu: avoid expensive square root computation	2016-02-17 00:27:16 +01:00