similar to: Xen clocksources and timekeeping wiki page

Howdy, I am having time-drift issues on my CentOS VM. I had referred to following documentation: http://wiki.centos.org/TipsAndTricks/VMWare_Server , however it didn't help. I used kickstart for creating this VM and I am listing important steps in ref to timekeeping issue. Any comments or suggestion would be appreciated. - CS. ------------------- # For EL5 virtual machines, Append the

Hi all, If you are using the kernel divider= option in your vmware quest, you are probably aware of the bugs reported at: https://bugzilla.redhat.com/show_bug.cgi?id=315471 Someone @redhat "confirmed" the fix is in the test kernel -92. I tried it but it seems to have the same problem as before - when used with clocksource=pit, it hangs on bootup. Wonder if some of you can test this

https://bugs.freedesktop.org/show_bug.cgi?id=98709 Bug ID: 98709 Summary: [NV50] clocksource: timekeeping watchdog on CPU2: Marking clocksource 'tsc' as unstable because the skew is too large Product: Mesa Version: 12.0 Hardware: x86-64 (AMD64) OS: Linux (All) Status:

This is really stupid question. But referring to: http://lists.centos.org/pipermail/centos/2009-October/083791.html I don't see any line related to ntpd in my /var/log/messages . Do I need to turn-on ntpd for timekeeping on VMs? Some people say not to use ntpd on VMs for timekeeping or is it ntpdate cron job? Can someone please elaborate on this? Thanks, Jonathan. -------------- next part

Running Dovecot 2.0.8 on 32bit Centos5.5. The machine is a VMWare ESX VM. I'm seeing a lot of warning messages in syslog as follows: 2011-01-14T11:45:37.315917+08:00 imap4 dovecot: imap: Warning: Time jumped forwards 105 seconds 2011-01-14T11:46:00.598006+08:00 imap4 dovecot: imap: Warning: Time jumped forwards 106 seconds 2011-01-14T11:46:25.364405+08:00 imap4 dovecot: imap: Warning: Time

We've noticed our fully-virtualized KVM guests' time keeps getting faster, despite running ntpd. A quick google reveals this to be a known problem with virtual guests. It seems there are a variety of solutions, some apparently vendor-specific. What is the best practice as of now for KVM guests? * Setting independent_wallclock=1 (or is that a xen-only thing)? * Passing kernel

Hi, I am running CentOS 5.3 32bit as a VirtualBox 3.0.0 guest running on Windows XP. The Windows host CPU usage is constantly at 50% although the CentOS guest is completely idle (i.e. 0.00 load average). I know this is a common problem related to the 1000Hz frequency that the CentOS kernel runs at. With previous versions of CentOS, I used the kernel-vm package [1] and it solved my problem.

Hi everyone, I have the problem with Xen domU's and timekeeping in dom0. Time in dom0 was incorrect by 5 hours due to wrong timezone assumed. Fixed it by ntpdate ntp.nist.gov. The time on a dom0 was changed. I didn't append xen.independent_wallclock=1 to sysctl.conf thus the time in all domU's was also changed. But THEY DIDN'T "KNOW" THAT! The 'date' output

Hi everyone, I have been struggling with having the clock of Linux VM's (including CentOS 4.6 and 5.1) running very fast under VMWare, no matter what I have tried. My platform: - AMD Turion X2 TL-60 - AMD 690 chipset with integrated Radeon x1250 (probably doesn't concern in this case) - Windows Vista Ultimate x64, all Windows Update patches loaded (no SP1 yet) - 4GB RAM - VMWare

On Wed, 3 Oct 2018, Andy Lutomirski wrote: > > On Oct 3, 2018, at 5:01 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > > Not all Hyper-V hosts support reenlightenment notifications (and, if I'm > > not mistaken, you need to enable nesting for the VM to get the feature - > > and most VMs don't have this) so I think we'll have to keep Hyper-V >

People at vmware have provided patches for RHEL 5 that aim to fix timekeeping issues in vmware guests. https://bugzilla.redhat.com/show_bug.cgi?id=463573 Description of problem (excerpt) : "In a virtual environment, timekeeping for RHEL 64 bit kernels can be problematic, since time is kept by counting timer interrupts for this kernel. The problem arises when the VM is descheduled for some

I''ve updated the wiki to reflect some more of the steps and workarounds that are currently needed. Please add your comments/updates/corrections: http://wiki.xensource.com/xenwiki/XenParavirtOps Cheers, Todd -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com

Hi, I have a virtual machine which fails to boot linux-4.1.8 while mounting file systems: > * Mounting local filesystem ... > ------------[ cut here ]------------ > kernel BUG at drivers/block/virtio_blk.c:172! > invalid opcode: 000 [#1] SMP > Modules linked in: pcspkr psmouse dm_log_userspace virtio_net e1000 fuse nfs lockd grace sunrpc fscache dm_snapshot dm_bufio dm_mirror

Hi, I have a virtual machine which fails to boot linux-4.1.8 while mounting file systems: > * Mounting local filesystem ... > ------------[ cut here ]------------ > kernel BUG at drivers/block/virtio_blk.c:172! > invalid opcode: 000 [#1] SMP > Modules linked in: pcspkr psmouse dm_log_userspace virtio_net e1000 fuse nfs lockd grace sunrpc fscache dm_snapshot dm_bufio dm_mirror

The current Linux scheduler makes one big assumption: that 1ms of CPU time is the same as any other 1ms of CPU time, and that therefore a process makes the same amount of progress regardless of which particular ms of time it gets. This assumption is wrong now, and will become more wrong as virtualization gets more widely used. It's wrong now, because it fails to take into account of several

The current Linux scheduler makes one big assumption: that 1ms of CPU time is the same as any other 1ms of CPU time, and that therefore a process makes the same amount of progress regardless of which particular ms of time it gets. This assumption is wrong now, and will become more wrong as virtualization gets more widely used. It's wrong now, because it fails to take into account of several

Stan, Thanks for the reply. In our case we have actually already done most of the work you suggested to no avail. We had rebuilt two new ntp servers that sync against two stratum 1 sources, and all our nfs clients, regardless of using dovecot, sync to those two machines. You bring up the difference between bare metal and hypervisor, and we are running these machines on vmware 4.0. All the

On 03/03/16 09:18, Patrick Masotta wrote: >>>> How so? > > it says they cannot emulate the timer interrupt very well; > that's what I understood... If it's the VMware document I'm thinking of (titled "Timekeeping in VMware Virtual Machines"), then the issue is that emulating the timer interrupt can cause a heavy load on the host if the guest timer is

Dear list(s), we are running a cluster of virtual machines on ganeti 2.15.2 on top of qemu-kvm 2.1.2. Hosts are Debian jessie (Kernel 3.16). We have big trouble with timekeeping on guests, no matter if these guests are lenny, squeeze, wheezy or jessie. Clock drifts heavily on some, others are fine. There is no obvious pattern on which guest this happens and on which not, but it seems the clock

Dear list(s), we are running a cluster of virtual machines on ganeti 2.15.2 on top of qemu-kvm 2.1.2. Hosts are Debian jessie (Kernel 3.16). We have big trouble with timekeeping on guests, no matter if these guests are lenny, squeeze, wheezy or jessie. Clock drifts heavily on some, others are fine. There is no obvious pattern on which guest this happens and on which not, but it seems the clock