Messages in this thread | | | Date | Fri, 2 Sep 2016 10:15:41 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 4/4] kvm: x86: export TSC offset to user-space |
| |
On Fri, 2 Sep 2016 09:43:01 -0400 Stefan Hajnoczi <stefanha@gmail.com> wrote:
> Can TSC offset changes occur at runtime? > > One example is vcpu hotplug where the tracing tool would need to fetch > the new vcpu's TSC offset after tracing has already started. > > Another example is if QEMU or the guest change the TSC offset while > running. If the tracing tool doesn't notice this then trace events will have > incorrect timestamps.
I believe there are tracepoints for these events. They would obviously need to be enabled for the tracer to catch them.
I would also recommend that they go into their own instance to make sure other events do not overwrite them.
-- Steve
| |