Messages in this thread | | | Date | Sun, 15 Jul 2012 07:00:19 -0600 | From | David Ahern <> | Subject | Re: perf with precise attribute kills all KVM based VMs |
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On 7/15/12 2:07 AM, Avi Kivity wrote: > On 07/12/2012 07:06 PM, Gleb Natapov wrote: >>> >>> Note the :pH this time. >> I am not sure what perf kvm does with :pH modifier, but H modifier does >> not make sense with perf kvm and should be reported as an error by perf tool. > > Maybe it should refer to the guest vs. the nested guest...
:H = host mode; you are thinking of :h for hypervisor mode. From perf-list documentation:
"Modifiers allow the user to restrict when events are counted with 'u' for user-space, 'k' for kernel, 'h' for hypervisor. Additional modifiers are 'G' for guest counting (in KVM guests) and 'H' for host counting (not in KVM guests)."
> > Well that's a horrible UI but we do need some way to distinguish among > the two. Samples from the nested guest's kernel will make no sense when > looking at the guest kernel. I guess we should default to exclude > nested guest mode. >
I catch a return flight in a couple of hours. I will send a summary email tonight to make sure we are on the same page with the problem, uses cases and patches.
David
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