From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH V4 1/2] perf & kvm: Enhance perf to collect KVM guest
 os statistics from host side
Date: Sat, 17 Apr 2010 22:16:58 +0300
Message-ID: <4BCA092A.8050308@redhat.com>
References: <1271403275.2078.509.camel@ymzhang.sh.intel.com> <4BC9FC9A.6050807@redhat.com> <20100417191308.GA25160@elte.hu>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Sheng Yang <sheng@linux.intel.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	oerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
	Jes Sorensen <Jes.Sorensen@redhat.com>,
	linux-kernel@vger.kernel.org, Zachary Amsden <zamsden@redhat.com>,
	Gleb Natapov <gleb@redhat.com>, tim.c.chen@intel.com,
	zhiteng.huang@intel.com,
	Arnaldo Carvalho de Melo <acme@infradead.org>
To: Ingo Molnar <mingo@elte.hu>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20100417191308.GA25160@elte.hu>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On 04/17/2010 10:13 PM, Ingo Molnar wrote:
> * Avi Kivity<avi@redhat.com>  wrote:
>
>    
>> On 04/16/2010 10:34 AM, Zhang, Yanmin wrote:
>>      
>>> Below is the kernel patch to enable perf to collect guest os statistics.
>>>
>>> Joerg,
>>>
>>> Would you like to add support on svm? I don't know the exact point to trigger
>>> NMI to host with svm.
>>>
>>> See below code with vmx:
>>>
>>> +		kvm_before_handle_nmi(&vmx->vcpu);
>>>   		asm("int $2");
>>> +		kvm_after_handle_nmi(&vmx->vcpu);
>>>
>>> Signed-off-by: Zhang Yanmin<yanmin_zhang@linux.intel.com>
>>>        
>> Can you please split it further?
>>
>> Patch 1 introduces perf_register_guest_info_callbacks() and related. Ingo
>> can merge this into a branch in tip.git. Patch 2 is just the kvm bits, I'll
>> apply that after merging the branch with patch 1. Patch 3 adds the
>> tools/perf changes.
>>
>> This way perf development can continue on tip.git, and kvm development can
>> continue on kvm.git, without the code bases diverging and requiring a merge
>> later.
>>      
> I'd like to pull the KVM bits from you into perf - so that there's a testable
> form of the changes. We can do that via a branch that has 1-2 changes, plus
> minimal conflicts down the line, right?
>    

We can try doing this (currently we don't, but this is simple enough 
that we could).  I'd still like 1-2 in two patches.

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