Re: [PATCH] cpu idle ticks show twice in xen pvm guest

From: Konrad Rzeszutek Wilk
Date: Mon Oct 10 2011 - 11:53:44 EST


On Wed, Oct 05, 2011 at 10:11:58PM -0700, Zhenzhong Duan wrote:
> Run below test on xen pvm.
> # x=$(cat /proc/stat | grep cpu0 | awk '{print $5}') && sleep 60 \
> && y=$(cat /proc/stat | grep cpu0 | awk '{print $5}') \
> && echo -e "X:$x\nY:$y\nIDLE:" $(echo "scale=3; ($y-$x)/6000*100" | bc)
>
> @ X:58562301
> @ Y:58574282
> @ IDLE: 199.600
>
> Normal idle percent should be around 100%.
> xen_timer_interrupt called account_idle_ticks to account hypervisor stolen idle ticks
> but these ticks will be accounted again when idle ticks restarted.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> Signed-off-by: Joe Jin <joe.jin@xxxxxxxxxx>

Please in the future also CC the maintainers (you can get that using
the scripts/get_maintainer.pl).

Jeremy, any thoughts?
>
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index 163b467..5dcbc91 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -151,7 +151,6 @@ static void do_stolen_accounting(void)
>
> ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked);
> __this_cpu_write(xen_residual_blocked, blocked);
> - account_idle_ticks(ticks);
> }
>
> /* Get the TSC speed from Xen */
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