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Date: Tue, 01 Feb 2011 14:01:56 +0100
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: [Qemu-devel] Re: [PATCH 2/3] Correct alarm deadline computation
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

On 2011-01-31 22:51, Paolo Bonzini wrote:
> When the QEMU_CLOCK_HOST clock was added, computation of its
> deadline was added to qemu_next_deadline, which is correct but
> incomplete.
> 
> I noticed this by reading the very convoluted rules whereby
> qemu_next_deadline_dyntick is computed, which miss QEMU_CLOCK_HOST
> when use_icount is true.  This patch inlines qemu_next_deadline
> into qemu_next_deadline_dyntick, and then corrects the logic to skip
> only QEMU_CLOCK_VIRTUAL when use_icount is true.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  qemu-timer.c |   15 +++++++++++----
>  1 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/qemu-timer.c b/qemu-timer.c
> index 60283a8..c19d0a2 100644
> --- a/qemu-timer.c
> +++ b/qemu-timer.c
> @@ -724,11 +724,18 @@ static uint64_t qemu_next_deadline_dyntick(void)
>      int64_t delta;
>      int64_t rtdelta;
>  
> -    if (use_icount)
> +    if (!use_icount && active_timers[QEMU_CLOCK_VIRTUAL]) {
> +        delta = active_timers[QEMU_CLOCK_VIRTUAL]->expire_time -
> +                     qemu_get_clock(vm_clock);
> +    } else {
>          delta = INT32_MAX;
> -    else
> -        delta = qemu_next_deadline();
> -
> +    }
> +    if (active_timers[QEMU_CLOCK_HOST]) {
> +        int64_t hdelta = active_timers[QEMU_CLOCK_HOST]->expire_time -
> +                 qemu_get_clock(host_clock);
> +        if (hdelta < delta)
> +            delta = hdelta;
> +    }
>      if (active_timers[QEMU_CLOCK_REALTIME]) {
>          rtdelta = (active_timers[QEMU_CLOCK_REALTIME]->expire_time -
>                   qemu_get_clock_ns(rt_clock));

Looks good to me. I guess this applies without the first patch? Then it
should go in (unless you are working on a new version for 1/3).

Thanks for fixing this.

Jan

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