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Subject: Re: [PATCH v1 0/2] perf: Drop leaked kernel samples
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     acme@kernel.org, jolsa@kernel.org, mingo@redhat.com,
        alexander.shishkin@linux.intel.com, me@kylehuey.com,
        Linux-kernel@vger.kernel.org, vincent.weaver@maine.edu,
        will.deacon@arm.com, eranian@google.com, namhyung@kernel.org,
        ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com
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 <11958be5-dc05-611b-6839-f1f6903c7ca8@linux.intel.com>
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From:   "Jin, Yao" <yao.jin@linux.intel.com>
Message-ID: <a8ba2079-b880-a145-a4e0-754d58ccdc8f@linux.intel.com>
Date:   Fri, 15 Jun 2018 16:24:49 +0800
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On 6/15/2018 4:12 PM, Peter Zijlstra wrote:
> On Fri, Jun 15, 2018 at 04:01:45PM +0800, Jin, Yao wrote:
> 
>> Bring more overhead to kernel if we zero the bits considering the number of
>> leaked samples may be not too small?
> 
> Keeping the samples at least allows you to know how many samples
> happened and such things.
> 

Yeah, agree, but a little bit overhead ...

>> And the skid information may be interesting (see example of hitting on
>> page_fault in previous mail). If we zero it, we will not know.
> 
> If you throw them out the window you also don't know, do you?
> 

Yes, default I can't know that window. I have to use sysctl to enable.

Thanks
Jin Yao