From: Xiao Guangrong <xiaoguangrong.eric@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Ingo Molnar <mingo@elte.hu>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Stefan Hajnoczi <stefanha@gmail.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 2/3] KVM: x86: add tracepoints to trace mmio begin and complete
Date: Fri, 03 Feb 2012 01:55:16 +0800 [thread overview]
Message-ID: <4F2ACE04.9040602@gmail.com> (raw)
In-Reply-To: <4F2AC9A0.7090904@redhat.com>
On 02/03/2012 01:36 AM, Avi Kivity wrote:
> On 02/02/2012 07:27 PM, Xiao Guangrong wrote:
>> From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
>>
>> 'perf kvm-events' will use kvm_exit and kvm_mmio(read...) to calculate
>> mmio read emulated time for the old kernel, in order to trace mmio read
>> event more exactly, we add kvm_mmio_begin to trace the time when mmio read
>> begins
>>
>> Also, add kvm_mmio_done to trace the time when mmio/pio is completed
>
> Previously, we discussed using the kvm_entry to do this. This reduces
> the number of tracepoints, and is backwards compatible. What was the
> conclusion?
>
Since using kvm_entry can cause lots of unnecessary calculated, these new two
tracepoints can let the result be exacter.
And, they are only used in new kernel, we will fall back to using kvm_entry if
they are not existing, that means it does not break backwards compatible.
next prev parent reply other threads:[~2012-02-02 17:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 17:25 [PATCH v2] KVM: perf: a smart tool to analyse kvm events Xiao Guangrong
2012-02-02 17:26 ` [PATCH v2 1/3] KVM: x86: move kvm_exit related definitions into kvm_exit.h Xiao Guangrong
2012-02-02 17:30 ` Avi Kivity
2012-02-02 17:48 ` Xiao Guangrong
2012-02-02 17:27 ` [PATCH v2 2/3] KVM: x86: add tracepoints to trace mmio begin and complete Xiao Guangrong
2012-02-02 17:36 ` Avi Kivity
2012-02-02 17:55 ` Xiao Guangrong [this message]
2012-02-02 17:56 ` Avi Kivity
2012-02-02 18:27 ` Xiao Guangrong
2012-02-02 18:43 ` Xiao Guangrong
2012-02-02 17:28 ` [PATCH v2 3/3] KVM: perf: kvm events analysis tool Xiao Guangrong
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