On Thu, Feb 2, 2012 at 05:36, Ron Frazier (NTP) <[email protected]> wrote: > The NTPD service always starts out at RealTime priority. I believe, based > on some loopstats files, that using RealTime priority creates periodic > spikes where the offset upwards of 35 ms or so. Also, the graph appears to > have random jerks in it. When I manually switch to Above Normal priority > using task manager, my offset excursions tend to stay within 15 ms and the > graph is smoother. I don't have enough data yet to prove my suspicions, > but, I've set other programs to RealTime priority before and found that it > destabilized the system.
Manually elevating processes to the realtime priority class is asking for trouble, particularly for GUI programs and programs which use a nontrivial amount of CPU. Processes at realtime priority levels can wedge the system by outcompeting critical system tasks. ntpd is designed to operate at elevated priority and sips CPU unless something is seriously misconfigured. In general, there's rarely a good reason to change priorities using Task Manager. > So, the question is, how do I force this process to always start at the > priority that I want, rather than having to change it each time in Task > Manager? > > I'd like to know other people's opinion on this matter. You can't choose the priority class for ntpd short of changing source and recompiling -- it always attempts to raise the priority to the realtime class. However, it will gracefully fall back to high priority class if the user account under which it is run is not granted the SeIncreaseBasePriorityPrivilege. From a command prompt, try: C:\windows\system32>showpriv SeIncreaseBasePriorityPrivilege 2 account(s) with the SeIncreaseBasePriorityPrivilege user right: BUILTIN\Administrators dlh-7551\ntp All accounts enumerated dlh-7551 is the machine name in my case. The ntp user is created by the Meinberg installer for ntpd using default options. If you remove SeIncreaseBasePriorityPrivilege, you can force ntpd to no higher than high priority class. That can be done using secpol.msc, navigating the tree to Local Policies\User Rights Assignment, then double-clicking on "Increase scheduling priority" to edit the list of user accounts granted that privilege. I doubt it will improve ntpd's performance, but if you find it does, please create an account and file a bug report at http://bugs.ntp.org/ Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
