Re: [ANNOUNCE] ktimers subsystem

Thomas Gleixner
2005-09-19T22:54:41Z

On Mon, 2005-09-19 at 16:39 -0600, Christopher Friesen wrote:
> Thomas Gleixner wrote:
>
> > We should rather ask glibc people why gettimeofday() / clock_getttime()
> > is called inside the library code all over the place for non obvious
> > reasons.
>
> From an app point of view, there are any number of reasons to check the
> time frequently.
>
> --debugging

Non standard case.

> --flight-recorder style logs

If you want to implement such stuff efficiently you rely on rdtscll() on
x86 or other monotonic easy accessible time souces and not on a
permanent call to gettimeofday.

> --if you've got timers in your application, you may want to check to
> make sure that you didn't get woken up early (the linux behaviour of
> returning unused time in select is not portable)

#ifdef is portable

Please beware me of red herrings. If application developers code with
respect to random OS worst case behaviour then they should not complain
that OS N is having an additional add instruction in one of the pathes.

tglx