Re: [PATCH] virtual sched_clock() for s390

[Srivatsa Vaddagiri]

On Thu, Jul 19, 2007 at 08:29:06AM -0700, Jeremy Fitzhardinge wrote:
> > - * Monotonic_clock - returns # of nanoseconds passed since time_init()
> > + * Scheduler clock - returns current time in nanosec units.
> > + * Now based on virtual cpu time to only account time the guest
> > + * was actually running.
> >   
> 
> Runn*ing*?  Does it include time the VCPU spends idle/blocked?  If not,
> then the scheduler won't be able to tell how long a process has been
> asleep.

Good point ..

I think we need a measure of both virtual and real time here - 
virtual for accounting task-execution time and real for
accounting sleep (and perhaps rq-wait?) time.

>  Maybe this doesn't matter (I had this problem in a version of
> Xen's sched_clock, and I can't say I saw an ill effects from it).

I guess it will show up as some corner case behaviour, which people are
yet to discover on virtual env.

-- 
Regards,
vatsa
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