Regular 16ms jump of NTP on Windows XP SP2 - NTP

This is a discussion on Regular 16ms jump of NTP on Windows XP SP2 - NTP ; I have a test setup with 12 IBM 3GHz dual core PC running either WinXp SP2 or SuSE Linux 9.3. I use an 'old' 933MHz Compaq PC running SuSE Linux 9.3 as NTP server (local clock), which otherwise does nothing. ...

+ Reply to Thread
Results 1 to 14 of 14

Thread: Regular 16ms jump of NTP on Windows XP SP2

  1. Regular 16ms jump of NTP on Windows XP SP2

    I have a test setup with 12 IBM 3GHz dual core PC running either WinXp SP2
    or SuSE Linux 9.3.
    I use an 'old' 933MHz Compaq PC running SuSE Linux 9.3 as NTP server
    (local clock), which otherwise does nothing.
    All other PCs use this node as unicast server, with a huffpuff filter
    setting of 7200 (e.g. 2h).
    All machines are connected through a professional switch from HP.

    Under Windows I use NTP 4.2.0a from Meinberg.

    When running Linux all machines are synchronized within 100-200us, with an
    occasional spike of 1-2ms when a system is loaded.
    This is great!

    When running Windows I see a spike of about 16ms in the loopstats-files on
    all the Windows nodes.
    The peculiar thing is that the spike occurs every 24 hours and 15 minutes
    per machine, but not at the same time on different machines.

    I have compiled NTP 4.2.2p for Windows, but it also shows the same spikes.

    Any ideas, what can cause this?
    _______________________________________________
    questions mailing list
    questions@lists.ntp.isc.org
    https://lists.ntp.isc.org/mailman/listinfo/questions


  2. Re: Regular 16ms jump of NTP on Windows XP SP2


    Bert Gøtterup Petersen wrote:
    > I have compiled NTP 4.2.2p for Windows, but it also shows the same spikes.


    If you compiled ntp4.2.2 for Windows are there any chances to make it
    public ? I need a new version of ntp, as the version 4.2.0b didn't work
    for me.

    Thanks !


  3. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert Gøtterup Petersen wrote:
    > When running Windows I see a spike of about 16ms in the loopstats-files on
    > all the Windows nodes.
    > The peculiar thing is that the spike occurs every 24 hours and 15 minutes
    > per machine, but not at the same time on different machines.


    Hmmm. Could this be an internal windows OS counter wrapping around?

    24 hours + 15 min = 86400 + 900 = 87300 s

    The original keyboard timer chip which generates the Dos 55 ms timer
    tick had a 64 K period which was close to but not exactly one hour...

    87300 / (24 * 65536) = 0.055038

    Yes! This is the original DOS timer tick period which Windows is still
    emulating for anything running inside a Dos box, as well as programs
    using very old Windows APIs.

    I'm willing to bet that the spike is caused by a once/day fixup of any
    residual errors caused by the fact that this emulation isn't totally
    accurate!

    Terje
    --
    -
    "almost all programming can be viewed as an exercise in caching"

  4. Re: Regular 16ms jump of NTP on Windows XP SP2

    Eugen,

    Eugen COCA wrote:
    > Bert Gøtterup Petersen wrote:
    >> I have compiled NTP 4.2.2p for Windows, but it also shows the same
    >> spikes.

    >
    > If you compiled ntp4.2.2 for Windows are there any chances to make it
    > public ? I need a new version of ntp, as the version 4.2.0b didn't work
    > for me.


    Neither the current -stable nor the -dev version of ntpd are stable under
    Windows, that's why Meinberg has not yet made a new GUI installer version
    available.

    If the xmas edition is also not stable on your machine (on most systems it
    is, but we've also heard about some where it isn't) you should downgrade to
    the fluxcap version which Heiko has recently made available for download:
    http://www.meinberg.de/english/sw/ntp.htm#ntp_nt

    This version has been pretty stable, and Heiko has merged in some newer
    patches (MM timer ..) to build the fluxcap version.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  5. Re: Regular 16ms jump of NTP on Windows XP SP2

    Hi

    I didn't think NTP used old timers like that...

    Any idea on how to avoid this?

    Bert

    "Terje Mathisen" wrote in message
    news:c4p4t3-ivr.ln1@osl016lin.hda.hydro.com...
    > Bert Gøtterup Petersen wrote:
    >> When running Windows I see a spike of about 16ms in the loopstats-files
    >> on all the Windows nodes. The peculiar thing is that the spike occurs
    >> every 24 hours and 15 minutes per machine, but not at the same time on
    >> different machines.

    >
    > Hmmm. Could this be an internal windows OS counter wrapping around?
    >
    > 24 hours + 15 min = 86400 + 900 = 87300 s
    >
    > The original keyboard timer chip which generates the Dos 55 ms timer tick
    > had a 64 K period which was close to but not exactly one hour...
    >
    > 87300 / (24 * 65536) = 0.055038
    >
    > Yes! This is the original DOS timer tick period which Windows is still
    > emulating for anything running inside a Dos box, as well as programs using
    > very old Windows APIs.
    >
    > I'm willing to bet that the spike is caused by a once/day fixup of any
    > residual errors caused by the fact that this emulation isn't totally
    > accurate!
    >
    > Terje
    > --
    > -
    > "almost all programming can be viewed as an exercise in caching"




  6. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert,

    Bert Gøtterup Petersen wrote:

    > Hi
    >
    > I didn't think NTP used old timers like that...
    >
    > Any idea on how to avoid this?


    Do you have ntpd running with the -M option? Otherwise if another programs
    ist run which modifies the Windows Multimedia Timer you will observe time
    steps like this.

    Unfortunately you don't write which exact version you have installed. There
    have been quite a few version each of which started with "4.2.0a@...".
    Both NTP versions which are currently available on our download page at
    http://www.meinberg.de/english/sw/ntp.htm#ntp_nt
    support the -M option and use it by default.

    Another possible reason would be another program which is run once per day
    and either tweaks the system time, or runs a task which lets the Windows
    clock loose a timer tick (which is about 16 milliseconds).

    We've had a customer where the Windows system time had lost 30 seconds (!)
    every night when his database application ran some maintenance tasks.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  7. Re: Regular 16ms jump of NTP on Windows XP SP2

    Martin

    Origionally I used your ntp-4.2.0b@1.1436mbg-xmas-o-win32-setup version.

    Today I started a client with the 'old' version
    ntp-4.2.0a@mbg-fluxcap-o-win32-setup.
    I expect to be able to report back tomorrow if the spike disapeared.

    These are test PC, so in fact they do nothing when we are not there, yet we
    see the spikes also in the weekends.
    We have been monitoring the systems, but without seeing any processes being
    started around the particular time.
    Also monitoring the network trafic showed no special activity.

    To add to my somewhat confused picture of the situation (sorry about that),
    I have observed that the problem
    disapeared on an IBM laptop after it was rebooted.

    Bert


    "Martin Burnicki" wrote in message
    news:i2i5t3-j21.ln1@gateway.py.meinberg.de...
    > Bert,
    >
    > Bert Gøtterup Petersen wrote:
    >
    >> Hi
    >>
    >> I didn't think NTP used old timers like that...
    >>
    >> Any idea on how to avoid this?

    >
    > Do you have ntpd running with the -M option? Otherwise if another programs
    > ist run which modifies the Windows Multimedia Timer you will observe time
    > steps like this.
    >
    > Unfortunately you don't write which exact version you have installed.
    > There
    > have been quite a few version each of which started with "4.2.0a@...".
    > Both NTP versions which are currently available on our download page at
    > http://www.meinberg.de/english/sw/ntp.htm#ntp_nt
    > support the -M option and use it by default.
    >
    > Another possible reason would be another program which is run once per day
    > and either tweaks the system time, or runs a task which lets the Windows
    > clock loose a timer tick (which is about 16 milliseconds).
    >
    > We've had a customer where the Windows system time had lost 30 seconds (!)
    > every night when his database application ran some maintenance tasks.
    >
    > Martin
    > --
    > Martin Burnicki
    >
    > Meinberg Funkuhren
    > Bad Pyrmont
    > Germany




  8. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert Gøtterup Petersen wrote:
    > Hi
    >
    > I didn't think NTP used old timers like that...


    NTP isn't!

    This is an OS/Windows HAL layer bug.

    > Any idea on how to avoid this?


    Replace the OS?
    :-)

    Terje
    >
    > Bert
    >
    > "Terje Mathisen" wrote in message
    > news:c4p4t3-ivr.ln1@osl016lin.hda.hydro.com...
    >> Bert Gøtterup Petersen wrote:
    >>> When running Windows I see a spike of about 16ms in the loopstats-files
    >>> on all the Windows nodes. The peculiar thing is that the spike occurs
    >>> every 24 hours and 15 minutes per machine, but not at the same time on
    >>> different machines.

    >> Hmmm. Could this be an internal windows OS counter wrapping around?
    >>
    >> 24 hours + 15 min = 86400 + 900 = 87300 s
    >>
    >> The original keyboard timer chip which generates the Dos 55 ms timer tick
    >> had a 64 K period which was close to but not exactly one hour...
    >>
    >> 87300 / (24 * 65536) = 0.055038
    >>
    >> Yes! This is the original DOS timer tick period which Windows is still
    >> emulating for anything running inside a Dos box, as well as programs using
    >> very old Windows APIs.
    >>
    >> I'm willing to bet that the spike is caused by a once/day fixup of any
    >> residual errors caused by the fact that this emulation isn't totally
    >> accurate!
    >>
    >> Terje
    >> --
    >> -
    >> "almost all programming can be viewed as an exercise in caching"

    >
    >



    --
    -
    "almost all programming can be viewed as an exercise in caching"

  9. Re: Regular 16ms jump of NTP on Windows XP SP2

    Martin,

    I am sad to have to report to you, that the 'old' fluxcap version also has
    this problem.
    Any idears for even older version I could try, or suggestions to where to
    look for the cause.

    I have monitored a system during a spike with the Microsoft tool TraceView
    from their DDK package .
    But it will take some time to work my way through the 50k entries...
    Any suggestions, what I should look for?

    Thanks
    Bert

    "Bert Gøtterup Petersen" wrote in message
    news:45002682$0$3496$edfadb0f@dread11.news.tele.dk ...
    > Martin
    >
    > Origionally I used your ntp-4.2.0b@1.1436mbg-xmas-o-win32-setup version.
    >
    > Today I started a client with the 'old' version
    > ntp-4.2.0a@mbg-fluxcap-o-win32-setup.
    > I expect to be able to report back tomorrow if the spike disapeared.
    >
    > These are test PC, so in fact they do nothing when we are not there, yet
    > we see the spikes also in the weekends.
    > We have been monitoring the systems, but without seeing any processes
    > being started around the particular time.
    > Also monitoring the network trafic showed no special activity.
    >
    > To add to my somewhat confused picture of the situation (sorry about
    > that), I have observed that the problem
    > disapeared on an IBM laptop after it was rebooted.
    >
    > Bert
    >
    >
    > "Martin Burnicki" wrote in message
    > news:i2i5t3-j21.ln1@gateway.py.meinberg.de...
    >> Bert,
    >>
    >> Bert Gøtterup Petersen wrote:
    >>
    >>> Hi
    >>>
    >>> I didn't think NTP used old timers like that...
    >>>
    >>> Any idea on how to avoid this?

    >>
    >> Do you have ntpd running with the -M option? Otherwise if another
    >> programs
    >> ist run which modifies the Windows Multimedia Timer you will observe time
    >> steps like this.
    >>
    >> Unfortunately you don't write which exact version you have installed.
    >> There
    >> have been quite a few version each of which started with "4.2.0a@...".
    >> Both NTP versions which are currently available on our download page at
    >> http://www.meinberg.de/english/sw/ntp.htm#ntp_nt
    >> support the -M option and use it by default.
    >>
    >> Another possible reason would be another program which is run once per
    >> day
    >> and either tweaks the system time, or runs a task which lets the Windows
    >> clock loose a timer tick (which is about 16 milliseconds).
    >>
    >> We've had a customer where the Windows system time had lost 30 seconds
    >> (!)
    >> every night when his database application ran some maintenance tasks.
    >>
    >> Martin
    >> --
    >> Martin Burnicki
    >>
    >> Meinberg Funkuhren
    >> Bad Pyrmont
    >> Germany

    >
    >




  10. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert "Gøtterup Petersen" wrote:
    []
    > When running Windows I see a spike of about 16ms in the
    > loopstats-files on all the Windows nodes.


    Have you enabled the multi-media timer? You shoudl do this.

    Cheers,
    David



  11. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert Gøtterup Petersen wrote:
    > Martin,
    >
    > I am sad to have to report to you, that the 'old' fluxcap version
    > also has this problem.
    > Any idears for even older version I could try, or suggestions to
    > where to look for the cause.
    >
    > I have monitored a system during a spike with the Microsoft tool
    > TraceView from their DDK package .
    > But it will take some time to work my way through the 50k entries...
    > Any suggestions, what I should look for?
    >
    > Thanks
    > Bert


    Enable the multi-media timers.

    David



  12. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert,

    Bert Gøtterup Petersen wrote:
    > Martin,
    >
    > I am sad to have to report to you, that the 'old' fluxcap version also has
    > this problem.
    > Any idears for even older version I could try, or suggestions to where to
    > look for the cause.


    Both the fluxcap version and the xmas version can modify the multimedia
    timer, if the -M option is given on the command line. Is this the case in
    your environment? You can check this using the service control manager, the
    -M option should be listed behind the ntpd.exe path in the properties page.

    If the -M option is there and time steps still happen then the time steps
    don't seem to be related to the MM timer stuff. There must be another
    reason, maybe a bad driver, another piece of software which modifies the
    system time, etc.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  13. Re: Regular 16ms jump of NTP on Windows XP SP2

    Martin,

    I have checked the service control manager, and I do use the -M option.
    As you stated earlier it there by default in the Meinberg installation.

    Bert

    "Martin Burnicki" wrote in message
    news:t3uit3-jrc.ln1@gateway.py.meinberg.de...
    > Bert,
    >
    > Bert Gøtterup Petersen wrote:
    >> Martin,
    >>
    >> I am sad to have to report to you, that the 'old' fluxcap version also
    >> has
    >> this problem.
    >> Any idears for even older version I could try, or suggestions to where to
    >> look for the cause.

    >
    > Both the fluxcap version and the xmas version can modify the multimedia
    > timer, if the -M option is given on the command line. Is this the case in
    > your environment? You can check this using the service control manager,
    > the
    > -M option should be listed behind the ntpd.exe path in the properties
    > page.
    >
    > If the -M option is there and time steps still happen then the time steps
    > don't seem to be related to the MM timer stuff. There must be another
    > reason, maybe a bad driver, another piece of software which modifies the
    > system time, etc.
    >
    > Martin
    > --
    > Martin Burnicki
    >
    > Meinberg Funkuhren
    > Bad Pyrmont
    > Germany




  14. Re: Regular 16ms jump of NTP on Windows XP SP2

    Bert,

    Bert Gøtterup Petersen wrote:

    > Martin,
    >
    > I have checked the service control manager, and I do use the -M option.
    > As you stated earlier it there by default in the Meinberg installation.


    OK, so NTP shouldn't be to blame on this.

    I'll see whether I can send you a little tool by mail which may help find
    out what's happening.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

+ Reply to Thread