Hi wu,
2010/8/15 wu zhangjin <wuzhangjin@xxxxxxxxx>:
>
> don't worry about it, the timekeeper solves it:
>
> kernel/time/timekeeping.c
>
> The r4k timer in most of the MIPS variants also only has a 32bits
> counter register, no problem with it:
>
> arch/mips/kernel/csrc-r4k.c
> arch/mips/kernel/cevt-r4k.c
>
> does xlr 732 also use such a timer (with MIPS count & compare
> registers of coprocessor0)?
>
yes, xlr732 use these two registers to generate timer interrupt,
with a frequency of 1GHZ
> If you need to get the time with high resolution, please use:
> getnstimeofday(), this function will return a linear time with the
> help of timekeeper(timekeeping_get_ns).
>
1) So hrtimer is based on xtime,
If CONFIG_NO_HZ is set , would xtime be updated on time and correctly ?
2) some question about __get_nsec_offset :
/* read clocksource: */
cycle_now = clocksource_read(clock);
/* calculate the delta since the last update_wall_time: */
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
if cycle_now is smaller than clock->cycle_last , say , cycle_now =
3 , cycle->cycle_last = 2^32-1 , then
cycle_delta = 3 - (2^32-1) = ?
> Regards,
> Wu Zhangjin
>
