ARM: 6786/1: enable CONFIG_KTIME_SCALAR
authorRob Herring <rob.herring@calxeda.com>
Fri, 4 Mar 2011 22:51:59 +0000 (23:51 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Wed, 9 Mar 2011 00:18:48 +0000 (00:18 +0000)
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 <rob.herring@calxeda.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/Kconfig

index ef41f7e39f693b81492b756d1d1cd16c48393c23..2fec7073f687ae92be652783424bc1a1b11dab94 100644 (file)
@@ -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