Re: [Patch 3/6] statistics infrastructure - prerequisite: timestamp

Andrew Morton
2006-05-24T22:05:47Z

Martin Peschke <mp3@de.ibm.com> wrote:
>
> +static inline int nsec_to_timestamp(char *s, unsigned long long t)
> +{
> + unsigned long nsec_rem = do_div(t, NSEC_PER_SEC);
> + return sprintf(s, "[%5lu.%06lu]", (unsigned long)t,
> + nsec_rem/NSEC_PER_USEC);
> +}

do_div() is actually defined in terms of u64, not unsigned long long.
Although afaict this will all work OK and all the usual type promotions
will dtrt.

Which begs the question: how _does_ the kernel represent nanoseconds? The
time-management code is a bit undecided (search for long long in
posix-cpu-timers.c, and for u64 in hrtimers.c). All a bit confused.

Anwyay. This function is too big and slow to be inlined..