ARM: 6786/1: enable CONFIG_KTIME_SCALAR

Use straight 64-bit values as 64-bit operations are fairly efficient on ARM.
Comparing the asm output with and without KTIME_SCALAR, using 64-bit math
generates clearly better code.

Comparing kernel/hrtimer.c .text size, it goes from 0x1414 to 0x119c with
this change.

Signed-off-by: Rob Herring <[email protected]>
Signed-off-by: Russell King <[email protected]>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ef41f7e39f693b81492b756d1d1cd16c48393c23..2fec7073f687ae92be652783424bc1a1b11dab94 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -63,6 +63,10 @@ config GENERIC_CLOCKEVENTS_BROADCAST
        depends on GENERIC_CLOCKEVENTS
        default y if SMP
 
+config KTIME_SCALAR
+       bool
+       default y
+
 config HAVE_TCM
        bool
        select GENERIC_ALLOCATOR