Re: [PATCH] remove blocked time accounting from xen "clockchip"

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Oct 20, 2011 at 05:02:41PM +0200, Laszlo Ersek wrote:
> On 10/20/11 16:35, Laszlo Ersek wrote:
> 
> >I'm convinced the patch is correct, and only the commit message might
> >need a small fix (mentioning cpu_idle()).

Hey Laszlo and Zhenzhong,

Rest assured - I haven't forgotten about the two time patches.. little
busy with some of the Fedore Core 16 kernel bugs.

> 
> I forgot to say that I also added counters to xen_timer_interrupt(),
> account_idle_ticks() (called from cpu_idle()), and the idle time
> branch of account_process_tick(). (The last one is reached from
> xen_timer_interrupt() via event_handler == &tick_nohz_handler, after
> highres=off was passed). When the VM was left alone, they were
> increasing in strict lock-step.
> 
> account_idle_time()
> 
>   <- account_idle_ticks()
>     <- tick_nohz_restart_sched_tick()
>       <- cpu_idle()
> 
>   <- account_process_tick()
>     <- update_process_times()
>       <- tick_nohz_handler() [highres=off]
>         <- xen_timer_interrupt()
> 
>       <- (tick_periodic())
>       <- (tick_sched_timer())
> 
> The timer interrupt appears to kick cpu_idle(), and the latter
> accounts for the time spent idly.
> 
> Laszlo
> 
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