similar to: Xen and timekeeping

I just tried to setup another domain on a server running 1 domain. When i try to start the domain it gives me an error Error: Device 0 (vif) could not be connected. Backend device not found. The entry in my xen config file for the disks is disk = [''phy:/dev/xen001/xen2-fun,sda1,w'',''phy:/dev/xen001/xen2-fun-swap,sda2,w''] Looking at /var/log/xend.log, i found

Hi all, recently I asked for help with a problem Samba had to write files (http://lists.samba.org/pipermail/samba/2002-November/085003.html, http://lists.samba.org/pipermail/samba/2002-November/085083.html). Since that hasn't solved, and since it occurs regardless of changes of the smb.conf, I'd like to post some passages of the smb log file (log level 4) of the attempt to copy a file to

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

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

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

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

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

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:

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

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

>>> 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

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

>>>How so? it says they cannot emulate the timer interrupt very well; that's what I understood...

>>> At the BIOS standard rate of 18.2Hz, no modern machine is even going to notice. Michael <<< I think they do when running a VM, That's why my Debian VM date is always indicating whatever, no matter how many times I reset the time of the day. (Running on a i7-3630QM host) For some reason they cannot emulate a good timer interrupt. Best, Patrick