Messages in this thread | | | Subject | Re: [patch 11/14] timekeeper read clock helper functions | From | john stultz <> | Date | Thu, 13 Aug 2009 16:30:18 -0700 |
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On Thu, 2009-08-13 at 17:40 +0200, Martin Schwidefsky wrote: > plain text document attachment (timekeeper-helper.diff) > From: Martin Schwidefsky <schwidefsky@de.ibm.com> > > Add timekeeper_read_clock_ntp and timekeeper_read_clock_raw and use > them for getnstimeofday, ktime_get, ktime_get_ts and getrawmonotonic. > > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: john stultz <johnstul@us.ibm.com> > Cc: Daniel Walker <dwalker@fifo99.com> > Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> > --- > kernel/time/timekeeping.c | 91 +++++++++++++++++++--------------------------- > 1 file changed, 38 insertions(+), 53 deletions(-) > > Index: linux-2.6/kernel/time/timekeeping.c > =================================================================== > --- linux-2.6.orig/kernel/time/timekeeping.c > +++ linux-2.6/kernel/time/timekeeping.c > @@ -95,6 +95,40 @@ static void timekeeper_setup_internals(s > timekeeper.mult = clock->mult; > } > > +/* Timekeeper helper functions. */ > +static inline s64 timekeeping_get_ns(void) > +{ > + cycle_t cycle_now, cycle_delta; > + struct clocksource *clock; > + > + /* read clocksource: */ > + clock = timekeeper.clock; > + cycle_now = clock->read(clock); > + > + /* calculate the delta since the last update_wall_time: */ > + cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; > + > + /* return delta convert to nanoseconds using ntp adjusted mult. */ > + return clocksource_cyc2ns(cycle_delta, timekeeper.mult, > + timekeeper.shift); > +}
Again, not a huge issue, but if we kept the read() out of this function and instead passed the cycle_now value in as a argument, we could also use this function in timekeeping_forward_now()
thanks -john
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