Message-ID: <4C0F5804.9080406@redhat.com>
Date: Wed, 09 Jun 2010 11:59:48 +0300
From: Avi Kivity <avi@redhat.com>
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To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
CC: LKML <linux-kernel@vger.kernel.org>, kvm@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Fr??d??ric Weisbecker <fweisbec@gmail.com>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Cyrill Gorcunov <gorcunov@gmail.com>, Lin Ming <ming.m.lin@intel.com>,
       Sheng Yang <sheng@linux.intel.com>,
       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>, zhiteng.huang@intel.com,
       tim.c.chen@intel.com
Subject: Re: [RFC] para virt interface of perf to support kvm guest os statistics
 collection in guest os
References: <1276054214.2096.383.camel@ymzhang.sh.intel.com>
In-Reply-To: <1276054214.2096.383.camel@ymzhang.sh.intel.com>
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On 06/09/2010 06:30 AM, Zhang, Yanmin wrote:
> From: Zhang, Yanmin<yanmin_zhang@linux.intel.com>
>
> Based on Ingo's idea, I implement a para virt interface for perf to support
> statistics collection in guest os. That means we could run tool perf in guest
> os directly.
>
> Great thanks to Peter Zijlstra. He is really the architect and gave me architecture
> design suggestions. I also want to thank Yangsheng and LinMing for their generous
> help.
>
> The design is:
>
> 1) Add a kvm_pmu whose callbacks mostly just calls hypercall to vmexit to host kernel;
> 2) Create a host perf_event per guest perf_event;
> 3) Host kernel syncs perf_event count/overflows data changes to guest perf_event
> when processing perf_event overflows after NMI arrives. Host kernel inject NMI to guest
> kernel if a guest event overflows.
> 4) Guest kernel goes through all enabled event on current cpu and output data when they
> overflows.
> 5) No change in user space.
>    

Other issues:

- save/restore support for live migration
- some way to limit the number of open handles (comes automatically with 
the table approach I suggested earlier)

-- 
error compiling committee.c: too many arguments to function

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