On 8/15/10, wilbur.chan <wilbur512@xxxxxxxxx> wrote: > I am planning to use linux 2.6.24 with hrtimer enabled and with > CONFIG_NO_HZ on mips xlr 732. > > > As we know, a monotomic increasing Clock Source is required to > support hrtimer, whose cycles could be retrieved from > clocksource->read function. > > However on xlr 732 ,there is only a 32 bits counter register, which > would overflow in 4s ( 2^32 / 1GHZ = 4). > > How to solve this ? > 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)? 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). Regards, Wu Zhangjin
