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Date: Mon, 22 Mar 2010 22:43:54 +0200
From: Avi Kivity <avi@redhat.com>
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To: Ingo Molnar <mingo@elte.hu>
CC: Anthony Liguori <anthony@codemonkey.ws>,
       Pekka Enberg <penberg@cs.helsinki.fi>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Sheng Yang <sheng@linux.intel.com>, linux-kernel@vger.kernel.org,
       kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
       oerg Roedel <joro@8bytes.org>, Jes Sorensen <Jes.Sorensen@redhat.com>,
       Gleb Natapov <gleb@redhat.com>, Zachary Amsden <zamsden@redhat.com>,
       ziteng.huang@intel.com, Arnaldo Carvalho de Melo <acme@redhat.com>,
       Fr?d?ric Weisbecker <fweisbec@gmail.com>,
       Gregory Haskins <ghaskins@novell.com>
Subject: Re: [RFC] Unify KVM kernel-space and user-space code into a single
 project
References: <20100322143212.GE14201@elte.hu> <4BA7821C.7090900@codemonkey.ws> <20100322155505.GA18796@elte.hu> <4BA796DF.7090005@redhat.com> <20100322165107.GD18796@elte.hu> <4BA7A406.9050203@redhat.com> <20100322173400.GB15795@elte.hu> <4BA7B87A.8060104@codemonkey.ws> <20100322192259.GD21919@elte.hu> <4BA7C4FF.3080407@codemonkey.ws> <20100322203215.GB18126@elte.hu>
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On 03/22/2010 10:32 PM, Ingo Molnar wrote:
> * Anthony Liguori<anthony@codemonkey.ws>  wrote:
>
>    
>> On 03/22/2010 02:22 PM, Ingo Molnar wrote:
>>      
>>>> Transitive had a product that was using a KVM context to run their
>>>> binary translator which allowed them full access to the host
>>>> processes virtual address space range.  In this case, there is no
>>>> kernel and there are no devices.
>>>>          
>>> And your point is that such vcpus should be excluded from profiling just
>>> because they fall outside the Qemu/libvirt umbrella?
>>>        
>> You don't instrument it the way you'd instrument an operating system so no,
>> you don't want it to show up in perf kvm top.
>>      
> Erm, why not? It's executing a virtualized CPU, so sure it makes sense to
> allow the profiling of it!
>    

It may not make sense to have symbol tables for it, for example it isn't 
generated from source code but from binary code for another architecture.

Of course, just showing addresses is fine, but you don't need qemu for that.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.