Fedora 9 clock sync problems

Discussion in 'Linux Virtual Machine' started by user#29, Jul 8, 2008.

  1. user#29

    user#29 Junior Member

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    I got Fedora 9 running as the Guest OS, but clock sync is terrible. I've set clocksource=pit but this doesn't help much, if at all. I lose more than a second per minute. (Not sure how bad the clock is, just for sure it's slow by >1s/m.) I have to run ntpdate in a cronjob every minute but even that is a very poor workaround since the clock jumps every minute. (ntpd doesn't seem to work at all, don't know why.)

    A Fedora 8 fresh install seems to work just fine without changing anything.

    Another issue with Fedora 9 is that no matter what I tell it the BIOS clock is set to (UTC or local time), at boot time the clock is always off by -7 hours (which is my time zone). This also works correctly in Fedora 8.

    I never had any problems with earlier Fedora's: 7, Core 6, Core 5 all worked fine. Centos 4 and 5 also work fine, as do Ubuntu d,e,f. Haven't played with g,h yet.
     
  2. John@Parallels

    John@Parallels Forum Maven

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    Fedora 9 is not yet officially supported, but it is strange, because I didn't met this,
    Did you try to install Parallels Tools?, this can cause situation, because Tools are not compatible
     
  3. user#29

    user#29 Junior Member

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    I have not tried Tools. I am running on a MBP 2.6GHz if that makes a difference.
     
  4. John@Parallels

    John@Parallels Forum Maven

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    I mean, Parallels Tools are not compatible with Fedora 9, and installation can cause this problem, I'll tried to check but was unable to reproduce situation, with time
     
  5. user#29

    user#29 Junior Member

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    are you saying that the clock should work correctly when not using Tools?
     
  6. John@Parallels

    John@Parallels Forum Maven

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    Yes, but as I mentioned I am not able to reproduce, and did not tested it yes,
    I am using Fedora 9 , only for testing, and RHEL in background, which works,and I didn't notice any time difference, (may be just didn't pay attention)
    May be you have some procedure to test it, or just leaving it alone, will show 1 minute back during one hour?
     
  7. user#29

    user#29 Junior Member

    Messages:
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    no specific testing procedure. just leave it alone, in one hour you will notice much more than 1 minute difference. really in 10 minutes you will notice the time difference.

    i just noticed this: when i boot my fedora 8 VM, it came up with cpu MHz 2210.119 and bogomips 9817.42. when i boot my fedora 9 VM, it came up with cpu MHz 1776.809 and bogomips 26850.51! that is, even though fedora 9 reports a much lower cpu speed, the bogomips is much higher! wierd. i guess cpu freq is measured, not reported by the hardware itself.
     
  8. user#29

    user#29 Junior Member

    Messages:
    16
    and besides the time difference, Fedora 9 isn't honoring the UTC vs local setting for the BIOS clock.
     
  9. user#29

    user#29 Junior Member

    Messages:
    16
    i just realized that both my fedora 8 and fedora 9 VMs lose time. i thought fedora 8 was working but i guess it isn't. what does work in fedora 8 though is it remembers that the BIOS clock is set to localtime, so when it boots it at least comes up with the time in the ballpark, instead of 7 hours behind.

    i also realized i was using SMP kernels. so i disabled that and booted with 'nosmp'.

    here is a quick test i did to see rougly how much time they lose in a minute. the test is inaccurate since 'sleep 60' doesn't actually sleep for 60s ...

    ntpdate time1.apple.com >/dev/null && sleep 60 && ntpdate time1.apple.com | awk '{print $10}'

    this will report the number of seconds lost in 1 minute (approx). if the output is a negative number it is the number of seconds gained.

    on my MBP 2.6 GHz both fedora 8 and fedora 9 report losing ~ 2.4s in *1 MINUTE* using the above command. wow, it's even worse than i thought.

    i haven't tried any other linux VMs with this command.
     
  10. John@Parallels

    John@Parallels Forum Maven

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    Ok, I will check it and reply tomorrow
     
  11. John@Parallels

    John@Parallels Forum Maven

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    In Fedora 9 reproduced:
    1. dmesg shows only UTC time - no difference time set in UTC or not
    2. time is not back but in my case it is just go ahead very quickly
    Both problem, I suppose related to fact that Parallels Tools are not installed.

    I will check on supported OSes too
     

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