[Twisted-Python] a question about monotonic clock
radix at twistedmatrix.com
Sun Oct 28 11:22:10 EDT 2012
On Sun, Oct 28, 2012 at 1:28 PM, <exarkun at twistedmatrix.com> wrote:
> On 05:57 am, dynamicgl at gmail.com wrote:
> >Hi All
> > I am quite concerned the ticket 2424 due to our system use
> >reactor.callLater almost anywhere. I know this issue is hard to be
> >otherwise It wouldn't exist for such a long time. So any work around
> >we getting fix it? The only way I can do is to disable NTP or stop
> >sync the time manually and then restart the process. The latter way is
> >to be accepted due to we have many machines.
> NTP does not cause problems with scheduling. NTP gradually slews the
> system clock - it does not introduce discontinuities (either forward or
> backward), it changes the rate at which time passes until the system
> clock agrees with the external clock.
> If you have systems configured to have their system clocks jump
> (`ntpdate` is sometimes used for this), fix them to not be configured
> this way.
> #2424 is primarily about user-initiated events, primarily on desktop
> machines - a user changing the system time, a user suspending the
> machine (and later unsuspending it). There's little or no reason for
> problems related to #2424 to ever come up on a properly maintained
I think that for *certain* uncommon types of applications, even the very
minor skewing of ntp can cause problems, but I wonder if gelin yan has
encountered real problems caused by the ntp skewing in the application
under discussion. Gelin, you did not describe what problem you're actually
having. If you would, that would benefit the continuation of the discussion.
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