On 2012-03-27 17:52, Paolo Bonzini wrote:
> Il 27/03/2012 17:08, Jan Kiszka ha scritto:
>>>> +#if defined(__sun__)
>>>> + if (timer_create(CLOCK_HIGHRES, &ev, &host_timer)) {
>>>> +#else
>>>> if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {
>>>> +#endif
>>>
>>> This should be #ifdef CLOCK_HIGHRES.
>>
>> Are we sure about this is and will remain equivalent and correct?
>>
>> Also, I found some man page that says CLOCK_HIGHRES is non-adjustable
>> while CLOCK_REALTIME is. That should make a difference in QEMU.
>
> Right, that's why I CCed you but then I forgot to ask the question.
>
> Does QEMU rely on CLOCK_REALTIME when "-rtc clock=host" is in use? A
> monotonic clock would work better when CLOCK_REALTIME jumps backwards
> (DST->solar). If the jump goes unnoticed, the alarm timer would have no
> timeout for an hour or so.
>
> Of course the opposite is true when going from solar time to DST; you
> move the realtime clock one hour forward and, with CLOCK_MONOTONIC, a
> host_clock timer to trigger an hour too late.