linux-kernel - Re: [RFC PATCH] perf tools: Don't set inherit bit for system wide evsel

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Date:	Mon, 26 Oct 2015 19:48:59 +0800
From:	"Wangnan (F)" <wangnan0@...wei.com>
To:	Adrian Hunter <adrian.hunter@...el.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	pi3orama <pi3orama@....com>
CC:	<linux-kernel@...r.kernel.org>,
	Alexei Starovoitov <ast@...mgrid.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Li Zefan <lizefan@...wei.com>
Subject: Re: [RFC PATCH] perf tools: Don't set inherit bit for system wide
 evsel



On 2015/10/26 17:25, Adrian Hunter wrote:
> On 26/10/15 11:08, Wangnan (F) wrote:
>>
>> evsel->system_wide is introduced by commit
>> bf8e8f4b832972c76d64ab2e2837a48397144887
>> (perf evlist: Add 'system_wide' option), but Adrian only introduced a new field
>> into perf, doesn't really make it active. Until now the only user of it is
>> arch/x86/util/intel-pt.c, but I'm not very sure the reason for IPT to use that
>> field.
>>
>> If I understand correctly, it should be okay for a normal system wide evsel
>> to have
>> this var set. I'll try another RFC for it.
> evsel->system_wide is for mixing evsels that aren't system-wide with ones
> that are.
>
> It might work to set it for all system-wide evsels but you will have to
> check the code and test it, because that would be using it in a new way
> that has never been tested.

I have check all occurance of system_wide I can found and found
only one behavior change which I believe should be okay. Please
have a look at [1].

Thank you.

[1] 
http://lkml.kernel.org/g/1445859720-146146-1-git-send-email-wangnan0@huawei.com

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