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-   -   Arm device system time unexpectedly change! (http://www.linuxquestions.org/questions/linux-newbie-8/arm-device-system-time-unexpectedly-change-930053/)

tybandara 02-18-2012 09:27 AM

Arm device system time unexpectedly change!
 
Hello all,
I have a Gumstix overo Arm device which runs linux kernel 2.6.34. I'm running a software program which relies on system time, so it is quite time critical. In the initialization process of this program it change the system time using the "date" command. But I happened to notice that after about 20 minutes updating the time, system time suddenly change by 2 minutes. I have configured the system timezone as UTC. After starting this time update process, each time I notice that there's this sudden time drift. I'm in deep trouble since my program heavily depend on system time. I would be so thankful for advice.

Thank you.
Thilina

suicidaleggroll 02-18-2012 11:40 AM

Is the NTP service running? I believe it's enabled by default.

tybandara 02-19-2012 10:41 PM

I found that the NTP is running. Thanks for the hint. I'm curious, I saw that this time changing takes place after about 20 minutes. Is there a configuration to set this timeout? Or is it inside the drift calculation algorithms of NTP?

suicidaleggroll 02-20-2012 09:22 AM

I'm not sure where the 20 min comes from, my guess is it's pinging multiple NTP servers and doing some internal calculations, and it's the network side that's holding things up (since processor usage is likely very low during this time). On my Overo systems it usually updates the time within about 3-4 minutes of boot.


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