Messages in this thread | | | Date | Thu, 20 Oct 2005 05:04:32 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: Ktimer / -rt9 (+custom) monotonic_clock going backwards. |
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On Thu, 20 Oct 2005, Ingo Molnar wrote:
> > * Steven Rostedt <rostedt@goodmis.org> wrote: > > > static inline nsec_t __get_nsec_offset(void) > > { > > cycle_t cycle_now, cycle_delta; > > nsec_t ns_offset; > > > > /* read clocksource */ > > cycle_now = read_clocksource(clock); > > > > /* calculate the delta since the last timeofday_periodic_hook */ > > cycle_delta = (cycle_now - cycle_last) & clock->mask; > > > > /* convert to nanoseconds */ > > ns_offset = cyc2ns(clock, ntp_adj, cycle_delta); > > > > /* Special case for jiffies tick/offset based systems > > * add arch specific offset > > */ > > ns_offset += arch_getoffset(); > > > > return ns_offset; > > } > > > > cycle_now is 32 bits. If the clocksource overflows (which it can in > > 30 seconds) the cyclec_delta will be wrong. > > isnt cycle_t 64 bits? >
Not anymore.
include/linux/time.h:
/* timeofday base types */ typedef s64 nsec_t; typedef unsigned long cycle_t;
-- Steve
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