similar to: patched kernel addressing timekeeping issues under vmware

In 780427f0e11 (Indicate that clock was set in the pvclock gtod notifier), logic was added to pass a CLOCK_WAS_SET notification to the pvclock notifier chain. While that patch added a action flag returned from accumulate_nsecs_to_secs(), it only uses the returned value in one location, and not in the logarithmic accumulation. This means if a leap second triggered during the logarithmic

In 780427f0e11 (Indicate that clock was set in the pvclock gtod notifier), logic was added to pass a CLOCK_WAS_SET notification to the pvclock notifier chain. While that patch added a action flag returned from accumulate_nsecs_to_secs(), it only uses the returned value in one location, and not in the logarithmic accumulation. This means if a leap second triggered during the logarithmic

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

Before 6.X Syslinux used a "Tick-less" timekeeping approach implemented in /core/bios.inc 6.X now implements a "Tick-counting" strategy (timer interrupt) implemented in /core/timer.inc I think this change presents issues when Sysylinux runs on Virtual Machines emulating a BIOS environment as they cannot correctly emulate the timer interrupt; see VMware's pdf:

Hello, I was thinking of creating a wiki page about Xen clocksources and timekeeping.. including dom0, PV guests and HVM guests. Dan and Jeremy: You guys might have some ideas for this page.. please let me know your thoughts :) Subjects to cover: - Xen hypervisor clocksources (hpet, acpi_pm, pit) - Xen dom0 clocksource, ntpd, etc - Xen PV guest clocksources, independent_wallclock, ntpd,

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

On 03/01/16 21:11, H. Peter Anvin via Syslinux wrote: > On 03/01/16 07:21, Patrick Masotta via Syslinux wrote: >> >> At the moment I'm seeing timing issues on TFTP transfers (lwIP depends >> on the new interrupt based timer). I have consistently detected >> >> multiple Requests, double ACKs, etc. All these problems seem to be >> >> sourced on the

> > There are quite a few; primarily we simply cannot make lwIP > (lpxelinux.0) work without it. However, pxelinux.0 should not depend on > this. I'm finding most of the problems on lpxelinux.0 > >Now, tickful timekeeping is wasteful, but this is a bootloader, and >functionality is the main concern. The "tickless" version still >depended on the BIOS

>>> 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 configured to run at a high rate. Michael <<< It seems it's more that that even at the regular rate... Best, Patrick

On 03/03/16 09:34, Patrick Masotta wrote: > > 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 > > configured to run at a high rate. > > It seems it's more that that even at the

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

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:

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

> Date: Fri, 17 Feb 2012 12:06:05 +0000 > From: Ian Campbell <Ian.Campbell@citrix.com> > To: Qrux <qrux.qed@gmail.com> > Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com> > Subject: Re: [Xen-devel] Xen domU Timekeeping (a.k.a TSC/HPET issues) > Message-ID: <1329480365.3131.50.camel@zakaz.uk.xensource.com> > Content-Type:

On 03/03/16 07:31, Patrick Masotta wrote: > > The timer interrupt works fine in at least KVM, Xen, VMware, and > > Hyper-V. (I've tested iPXE in all of those virtual environments, and > > iPXE relies on the timer interrupt actually triggering a call to an ISR > > within the VM.) > > Well, that contradicts what the VMware document says. How so? Michael

From: David Vrabel <david.vrabel@citrix.com> Instead of passing multiple bools to timekeeping_updated(), define flags and use a single ''action'' parameter. It is then more obvious what each timekeeping_update() call does. Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- kernel/time/timekeeping.c | 21 ++++++++++++--------- 1 files changed, 12

Can anyone comment on the easiest way to get the PPS Kit kernel patch to work on a CentOS-5 system? I'd rather not use a plain vanilla kernel. http://www.kernel.org/pub/linux/daemons/ntp/PPS/

On 03/01/16 07:21, Patrick Masotta via Syslinux wrote: > > At the moment I'm seeing timing issues on TFTP transfers (lwIP depends > on the new interrupt based timer). I have consistently detected > > multiple Requests, double ACKs, etc. All these problems seem to be > > sourced on the now unreliable timeouts. > I have used TFTP on the same (BIOS VM) scenarios with

On 02/03/16 22:47, Patrick Masotta via Syslinux wrote: > Not really, a virtual environment can easily emulate the BIOS_timer at 0x046C > but it has problems emulating a "real" timer interrupt to be hooked... > That's the real problem. The timer interrupt works fine in at least KVM, Xen, VMware, and Hyper-V. (I've tested iPXE in all of those virtual environments, and

>>> > Not really, a virtual environment can easily emulate the BIOS_timer at 0x046C > but it has problems emulating a "real" timer interrupt to be hooked... > That's the real problem. The timer interrupt works fine in at least KVM, Xen, VMware, and Hyper-V. (I've tested iPXE in all of those virtual environments, and iPXE relies on the timer interrupt