[ntp:questions] Power-saving patch to NTP

David Woolley david at ex.djwhome.demon.co.uk.invalid
Sun May 18 11:13:35 UTC 2008


Uwe Klein wrote:
> Danny Mayer wrote:
> 
>> It's not doing nothing. If the CPU is on standby nothing, including 
>> ntpd, should be running.
> 
> ntp would then need to accomodate thinks like a "sleep mode"?
> and a "trigger" of type "Query the associations now"
> ( on linux forex be d-bus aware? )

The impression I get is that ntpd should be treated as infrastructure, 
and have power management states, but Red Hat are treating it as an 
errant application that needs to be modified to avoid upsetting the 
power management apple cart.  E.g. after resume from RAM, it needs to 
progress the clock discipline algorithm forwards (including extra 
corrections for temperature excursions) before anything is allowed to 
read the value of the clock, and after resume from disk, it should 
probably do a restart.

The latter greatly increases the importance of fast convergence, and 
without specific compensation for temperature variation, even resume 
from RAM needs the ability to respond fast to frequency hits, possibly 
conditioned on just having done a resume.

> 
> The basic assumptions about the host systems ntp runs on are
> changing fast!




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