time/jiffies: Allow CLOCK_TICK_RATE to be undefined

CLOCK_TICK_RATE is a legacy constant that defines the timer
device's granularity. On hardware with particularly coarse
granularity, this constant is used to reduce accumulated
time error when using jiffies as a clocksource, by calculating
the hardware's actual tick length rather then just assuming
it is 1sec/HZ.

However, for the most part this is unnecessary, as most modern
systems don't use jiffies for their clocksource, and their
tick device is sufficiently fine grained to avoid major error.

Thus, this patch allows an architecture to not define
CLOCK_TICK_RATE, in which case ACTHZ defaults to (HZ << 8).

Signed-off-by: Catalin Marinas <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Andrew Morton <[email protected]>
[ Commit log & intention tweaks ]
Signed-off-by: John Stultz <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions