Messages in this thread | | | From | "Albert D. Cahalan" <> | Subject | Re: HZ, preferably as small as possible | Date | Mon, 15 Jul 2002 14:43:00 -0400 (EDT) |
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Russell King writes: > On Mon, Jul 15, 2002 at 12:07:18PM -0400, Albert D. Cahalan wrote:
>> You have 64, 128, and 1000. See for yourself. >> >> arch-cl7500/param.h #define HZ 100 >> arch-epxa10db/param.h #define HZ 100 >> arch-integrator/param.h #define HZ 100 >> arch-l7200/param.h #define HZ 128 >> arch-shark/param.h #define HZ 64 >> arch-tbox/param.h #define HZ 1000 >> >> I need to support all of that with one binary. >> So I'm stuck with: > > Lets look more closely: > > #ifndef HZ > #define HZ 100 > #endif > #if defined(__KERNEL__) && (HZ == 100) > #define hz_to_std(a) (a) > #endif > > And: > > $ grep hz_to_std arch-*/param.h > arch-l7200/param.h:#define hz_to_std(a) ((a * HZ)/100) > arch-shark/param.h:#define hz_to_std(a) ((a * HZ)/100)
Won't that overflow in 3 or 4 days?
> As I said, tbox is broken, so ignore that.
OK.
> And hz_to_std gets used (fs/proc/array.c): > > hz_to_std(task->times.tms_utime), > hz_to_std(task->times.tms_stime), > hz_to_std(task->times.tms_cutime), > hz_to_std(task->times.tms_cstime),
Now look in the 2.4.xx kernel source.
> So merely grepping for HZ doesn't actually tell you anything. > > All /proc values are in 100Hz units on ARM.
Since kernel 2.5.25 it looks like. I must support the 2.4.xx kernels at least, and 2.2.xx is still pretty popular.
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