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SubjectRe: /proc or ps tools bug? 2.6.3, time is off
Tim Schmielau wrote:
>>diff -Nru a/include/linux/times.h b/include/linux/times.h
>>--- a/include/linux/times.h Tue Apr 13 15:00:25 2004
>>+++ b/include/linux/times.h Tue Apr 13 15:00:25 2004
>>@@ -7,7 +7,12 @@
>> #include <asm/param.h>
>>
>> #if (HZ % USER_HZ)==0
>>-# define jiffies_to_clock_t(x) ((x) / (HZ / USER_HZ))
>>+static inline long jiffies_to_clock_t(long x)
>>+{
>>+ u64 tmp = (u64)x * TICK_NSEC;
>>+ x = do_div(tmp, (NSEC_PER_SEC / USER_HZ));
>>+ return (long)tmp;
>>+}
>> #else
>> # define jiffies_to_clock_t(x) ((clock_t) jiffies_64_to_clock_t((u64) x))
>> #endif
>
>
> Excuse me for barging in lately and innocently, but I find this patch
> hard to comprehend:
> - shouldn't a foo_to_clock_t() function return a clock?
> - the x = seems superfluous
> - the #if is not a shortcut anymore, so why keep it?
> Shouldn't this patch be more like the following
> (completely untested)?
>
> Tim
>
>
> diff -urp --exclude-from dontdiff linux-2.6.5/include/linux/times.h linux-2.6.5-jfix1/include/linux/times.h
> --- linux-2.6.5/include/linux/times.h 2004-02-04 04:43:09.000000000 +0100
> +++ linux-2.6.5-jfix1/include/linux/times.h 2004-04-14 13:48:57.000000000 +0200
> @@ -6,11 +6,16 @@
> #include <asm/types.h>
> #include <asm/param.h>
>
> -#if (HZ % USER_HZ)==0
> -# define jiffies_to_clock_t(x) ((x) / (HZ / USER_HZ))
> -#else
> -# define jiffies_to_clock_t(x) ((clock_t) jiffies_64_to_clock_t((u64) x))
> -#endif
> +static inline clock_t jiffies_to_clock_t(long x)
> +{
> +#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
> + return x / (HZ / USER_HZ);
> +#else
> + u64 tmp = (u64)x * TICK_NSEC;
> + do_div(tmp, (NSEC_PER_SEC / USER_HZ));
> + return (long)tmp;
> +#endif
> +}
>
> static inline unsigned long clock_t_to_jiffies(unsigned long x)
> {
>
It does look a bit better. Takes into account the issue of TICK_NSEC being what
it is.

--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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