Currently we are wasting time calling the generic calibrate_delay() function. We don't need it since our implementation of __delay() is based on the CPU timebase. So instead, we use our own small implementation that initializes loops_per_jiffy to something sensible to make the few users like spinlock debug be happy
Signed-off-by: Benjamin Herrenschmidt <[email protected]> --- arch/powerpc/Kconfig | 4 ---- arch/powerpc/kernel/time.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 4 deletions(-) --- linux-work.orig/arch/powerpc/Kconfig 2009-06-10 16:09:35.000000000 +1000 +++ linux-work/arch/powerpc/Kconfig 2009-06-10 16:13:00.000000000 +1000 @@ -93,10 +93,6 @@ config GENERIC_HWEIGHT bool default y -config GENERIC_CALIBRATE_DELAY - bool - default y - config GENERIC_FIND_NEXT_BIT bool default y Index: linux-work/arch/powerpc/kernel/time.c =================================================================== --- linux-work.orig/arch/powerpc/kernel/time.c 2009-06-10 16:09:35.000000000 +1000 +++ linux-work/arch/powerpc/kernel/time.c 2009-06-10 16:13:00.000000000 +1000 @@ -52,6 +52,7 @@ #include <linux/jiffies.h> #include <linux/posix-timers.h> #include <linux/irq.h> +#include <linux/delay.h> #include <asm/io.h> #include <asm/processor.h> @@ -1143,6 +1144,15 @@ void div128_by_32(u64 dividend_high, u64 } +/* We don't need to calibrate delay, we use the CPU timebase for that */ +void calibrate_delay(void) +{ + /* Some generic code (such as spinlock debug) use loops_per_jiffy + * as the number of __delay(1) in a jiffy, so make it so + */ + loops_per_jiffy = tb_ticks_per_jiffy; +} + static int __init rtc_init(void) { struct platform_device *pdev; _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
