Re: [RFC][PATCH v2 4/7] taskstats: Add per task steal time accounting

From: Avi Kivity
Date: Tue Nov 16 2010 - 11:39:45 EST


On 11/16/2010 05:45 PM, Peter Zijlstra wrote:

In fact, kvm seems to already have these tracepoints: kvm_exit/kvm_entry
and it has a separate excplicit hypercall tracepoint as well:
kvm_hypercall.
But the kvm tracepoints are used when Linux is the hypervisor, no? For our
situation that would be a tracepoint in z/VM - or the equivalent. This is
out of scope of this patch.
Ah crud, you might be right.. Avi could a kvm guest generate events on
vcpu enter/exit?

No. Hypercalls are voluntary and known, but most exits are involuntary and unknown to the guest. Any memory access can generate a page fault, and any host interrupt will exit the guest.
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