Re: sysUpTime question
Bart Van Assche <[email protected]>
| Newsgroups | gmane.network.net-snmp.user |
|---|---|
| Message-ID | <[email protected]> |
On Sun, Nov 29, 2009 at 7:39 PM, Dave Shield <[email protected]>wrote: > 2009/11/29 <[email protected]>: > > the issue could have been resolved by sampling the > > system uptime when the snmp daemon starts, and using > > it to calculate the sysUptime value, instead of relaying > > on the system clock > > But the value of system uptime when the agent starts is 0, > by definition. > > The SNMP agent needs to relate this point to future > timestamps, and does so by using the local clock. > > Yes - if that clock time changes, you've got a problem. > Computing the system uptime via gettimeofday() is wrong. A better solution would be to let get_uptime() in snmplib/system.c compute the system uptime using methods that do not depend on the wall clock time, e.g. clock_gettime(CLOCK_MONOTONIC) on POSIX systems that support monotonic clocks or GetTickCount() on Windows systems. Note: the clock rate of CLOCK_MONOTONIC takes the clock drift computed by the NTP algorithm in account, while GetTickCount() does not. Bart. ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Net-snmp-users mailing list [email protected] Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users