Re: [Xen-ia64-devel] [PATCH][3/3] Steal time accounting forPVdomain/IA64 TAKE2

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Fri, May 09, 2008 at 04:31:06PM +0900, Atsushi SAKAI wrote:
> 1)about new_itm  value.
> "new_itm" is set from local_cpu_data->itm_next
> (later I use this as itm_next) 
> at header part of timer_interrupt.
> 
> So it does not effect itm_next changes in
> consider_steal_time().
> 
> 2)The difference of following time 
> > > > ia64_get_itc() - (the itc of the last time 
> > > >                   the timer interrupt handler was invoked)
> 
> Every time should set next ITM like follows.
> local_cpu_data->itm_next(itm_next)+local_cpu_data->itm_delta(itm_delta).
> 
> So "guessed last itc" should be itm_next - itm_delta
> This itm_delta effect is already considered on stolentick++;

Really?
consider_steal_time()
        unsigned long delta_itm = 0, stolentick = 0;
        delta_itm += local_cpu_data->itm_delta * (stolen + blocked);
        local_cpu_data->itm_next = delta_itm + new_itm;

Shouldn't be delta_itm added one more local_cpu_data->itm_delta?
If consider_steal_time() returns 0, the while loop in timer_interrupt()
may add local_cpu_data->itm_delta more than once.
What's your assumption here?

-- 
yamahata

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