search for: system_timestamp

Hi, I have done some debugging to find out the root cause of bug 1282, which has the following symptoms with paravirtualized guests: - after a live migrate, the time on the guest can jump - after a live migrate, the guest "forgets" to wake up processes - after a domU save, dom0 reboot and domU restore, the time is correct but processes are not woken up from sys_nanosleep The problem

Respin of the paravirt clock patch series. On the host side the kvm paravirt clock is made compatible with the xen clock. On the guest side some xen code has been factored out into a separate source file shared by both kvm and xen clock implementations. This time it should work ok for kvm smp guests ;) cheers, Gerd

Respin of the paravirt clock patch series. On the host side the kvm paravirt clock is made compatible with the xen clock. On the guest side some xen code has been factored out into a separate source file shared by both kvm and xen clock implementations. This time it should work ok for kvm smp guests ;) cheers, Gerd

paravirt clock source patches, next round, with a bunch of changes in the host code according to Avi's review comments and some minor code tweaks. cheers, Gerd

paravirt clock source patches, next round, with a bunch of changes in the host code according to Avi's review comments and some minor code tweaks. cheers, Gerd

...d master_cycle_now come from > CLOCK_BOOTTIME. So the kvmclock and kernel clock drift apart at a > rate given by the frequency shift and then suddenly agree again every > time the pvclock data is updated. Yes. > Is there a reason to do it this way? Since pvclock updates which update system_timestamp are expensive (must stop all vcpus), they should be avoided. So only HW TSC counts, and used as offset against vcpu's tsc_timestamp.

...d master_cycle_now come from > CLOCK_BOOTTIME. So the kvmclock and kernel clock drift apart at a > rate given by the frequency shift and then suddenly agree again every > time the pvclock data is updated. Yes. > Is there a reason to do it this way? Since pvclock updates which update system_timestamp are expensive (must stop all vcpus), they should be avoided. So only HW TSC counts, and used as offset against vcpu's tsc_timestamp.

...nt cpus? That is, if xen sends a VIRQ_TIMER to vcpu0, backed by cpu0, is it possible for that interrupt to be handled by vcpu1, backed by cpu1 ? After putting in some debug code in to timer_interrupt in linux, I can see that when we get a "Time went backwards" message, that shadow->system_timestamp+offset is significantly behind the previous value of processed_system_time, and that the previous value was set by the OTHER vcpu. Timer ISR/0: Time went backwards: delta=-44611438 cpu_delta=15388562 shadow=69081255546 off=254172405 processed=69380039389 cpu_processed=69320039389 last_modified=...

paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. Some minor tweaks after super-fast review by Jeremy. The queue is on top of the kvm git tree. The first two patches should have no kvm dependencies and should apply to linus tree just fine. cheers, Gerd

paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. Some minor tweaks after super-fast review by Jeremy. The queue is on top of the kvm git tree. The first two patches should have no kvm dependencies and should apply to linus tree just fine. cheers, Gerd

paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. cheers, Gerd

paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. cheers, Gerd

...CK_BOOTTIME. So the kvmclock and kernel clock drift apart at a > > rate given by the frequency shift and then suddenly agree again every > > time the pvclock data is updated. > > Yes. > > > Is there a reason to do it this way? > > Since pvclock updates which update system_timestamp are expensive (must stop all vcpus), > they should be avoided. > Fair enough. > So only HW TSC counts makes sense. >, and used as offset against vcpu's tsc_timestamp. > Why don't you just expose CLOCK_MONTONIC_RAW or CLOCK_MONOTONIC_RAW plus suspend time, though? Then y...

On Mon, Oct 08, 2018 at 10:38:22AM -0700, Andy Lutomirski wrote: > On Mon, Oct 8, 2018 at 8:27 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > On Sat, Oct 06, 2018 at 03:28:05PM -0700, Andy Lutomirski wrote: > > > On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > > > On Thu, Oct 04, 2018

On Mon, Oct 08, 2018 at 10:38:22AM -0700, Andy Lutomirski wrote: > On Mon, Oct 8, 2018 at 8:27 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > On Sat, Oct 06, 2018 at 03:28:05PM -0700, Andy Lutomirski wrote: > > > On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > > > On Thu, Oct 04, 2018

Unlike full virtualization in which the virtual machine provides the same platform interface as running natively on the hardware, paravirtualization requires modification to the guest operating system to work with the platform interface provided by the hypervisor. Xen was designed with performance in mind. Calls to the hypervisor are minimized, batched if necessary, and non-critical codepaths

Hi Andi, This patch series implements the Linux Xen guest as a paravirt_ops backend. The features in implemented this patch series are: * domU only * UP and SMP guest support (NEW!) * dynamic ticks (NEW!) * writable pagetables, with late pinning/early unpinning (no shadow pagetable support) * supports both PAE and non-PAE modes (non-PAE may be broken at the moment) * xen hvc console

Hi Andi, This patch series implements the Linux Xen guest as a paravirt_ops backend. The features in implemented this patch series are: * domU only * UP and SMP guest support (NEW!) * dynamic ticks (NEW!) * writable pagetables, with late pinning/early unpinning (no shadow pagetable support) * supports both PAE and non-PAE modes (non-PAE may be broken at the moment) * xen hvc console

Hi Andi, This patch series implements the Linux Xen guest as a paravirt_ops backend. The features in implemented this patch series are: * domU only * UP and SMP guest support (NEW!) * dynamic ticks (NEW!) * writable pagetables, with late pinning/early unpinning (no shadow pagetable support) * supports both PAE and non-PAE modes (non-PAE may be broken at the moment) * xen hvc console

Unlike full virtualization in which the virtual machine provides the same platform interface as running natively on the hardware, paravirtualization requires modification to the guest operating system to work with the platform interface provided by the hypervisor. Xen was designed with performance in mind. Calls to the hypervisor are minimized, batched if necessary, and non-critical codepaths