Re: [libvirt] time: event poll may become un-triggerable after changing system clock.
On Wed, May 13, 2015 at 08:54:49AM +0800, zhang bo wrote:
On 2015/5/12 16:56, Daniel P. Berrange wrote:
> On Tue, May 12, 2015 at 04:14:37PM +0800, zhang bo wrote:
>> So, Is there any other better solution? thanks in advance.
>
> Simply don't change the system time by massive deltas. Libvirt is not going
> to be the only app to be affected. As you mention it is going to hit the
> pthread_cond_wait() call which will likely affect pretty much every single
> non-trivial process running on the system. I'd expect other apps have much
> the same problem with calculating poll sleeps too.
>
> If you need to massively change the system time this should be done at
> single user mode, or do a reboot. Once a system is running it should be
> kept synced with NTPD which will only ever change system time in very
> small increments and so once cause thsi problem.
Would you please explain more about what "single user mode"
mean here? and does "reboot" refers to
"rebooting the os" or "rebooting the process libvirtd"? I think
it's "the process", right?
Single user mode is where you boot the OS such that you only have a
root shell running. No other processes are present. So you can safely
mess around with core system settings like hardware clock without
confusing any apps that are running. I mean rebooting the OS, not
restarting the process
Regards,
Daniel
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