1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 <2015> 2016 2017 2018 2019 2020 2021 2022 2023 2024 | Index | 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 <2015> 2016 2017 2018 2019 2020 2021 2022 2023 2024 |
<== Date ==> | <== Thread ==> |
---|
Subject: | Re: setting NTP time sync interval on vxWorks |
From: | Ralph Lange <[email protected]> |
To: | EPICS Tech-Talk <[email protected]> |
Date: | Fri, 03 Jul 2015 11:33:16 +0200 |
Hi Yuliang,The NTP sync interval is a compile time constant, thus it cannot be changed at run time.
One question, though.Your time report shows that the measured tick rate is 60.007 Hz, which is a difference of about 2 us per tick, 120 us per second, 7.2 ms per minute. Time resolution is in ticks, i.e. 16.67 ms. That means the NTP sync will skip a single tick in the counter every two or three minutes.
Why do you want to change the sync interval?Setting it longer will make the situation worse: more than one tick will be skipped at larger intervals. Setting it shorter will increase network traffic without changing the situation much: a deviation of 7.2 ms per minute will always be corrected by skipping one tick after between two and three minutes.
Cheers, ~Ralph On 03/07/2015 10:36, Zhang Yuliang wrote:
Hi all, I want to know how to set the NTP time sync interval on vxWorks. The output of "NTPTime_Report 1" shows the default interval is 60 seconds: timingMain>NTPTime_Report 1 NTP driver is synchronized with server Syncronization interval = 60.0 seconds Last synchronized at 2015-07-03 16:06:19.062927 OS tick rate = 60 Hz (nominal) Measured tick rate = 60.007 Hz NTP Server = 10.1.201.31 value = 0 = 0x0 I can modify the variable "NTPTimeSyncInterval" in file $(EPICS_BASE)\src\libCom\osi\osiNTPTime.c to change the sync interval. Is there a command can be used in ioc shell? Best regards, Zhang Yuliang