linux-kernel - Re: [PATCH 07/13] perf evlist: Fix creation of cpu map

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Date:	Fri, 27 Apr 2012 09:32:09 -0600
From:	David Ahern <dsahern@...il.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
CC:	Namhyung Kim <namhyung.kim@....com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 07/13] perf evlist: Fix creation of cpu map

On 4/27/12 9:08 AM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Apr 27, 2012 at 09:16:18AM +0900, Namhyung Kim escreveu:
>> Hi,
>>
>> On Thu, 26 Apr 2012 15:22:55 -0600, David Ahern wrote:
>>> On 4/26/12 3:12 PM, Namhyung Kim wrote:
>>>> Hmm.. No, I can reproduce it without any of this series. And now I think
>>>> that it is not related to the number of cpus. On my 4 core (no
>>>> hyperthreading) machine at home, the result was same.
>>>>
>>>> BTW, did you change sysctl settings?
>>>>
>>>>     $ cat /sys/devices/system/cpu/online
>>>>     0-3
>>>>     $ grep . /proc/sys/kernel/perf_event_*
>>>>     /proc/sys/kernel/perf_event_max_sample_rate:100000
>>>>     /proc/sys/kernel/perf_event_mlock_kb:516
>>>>     /proc/sys/kernel/perf_event_paranoid:1
>>>
>>> $ grep . /proc/sys/kernel/perf_event_*
>>> /proc/sys/kernel/perf_event_max_sample_rate:100000
>>> /proc/sys/kernel/perf_event_mlock_kb:516
>>> /proc/sys/kernel/perf_event_paranoid:-1
>>>
>>> That last one is the key. I have it set to not paranoid and usually
>>> run perf a non-root user.
>>>
>>
>> That's exactly what I want to see :). On perf_mmap() we have:
>>
>> 	if ((locked>  lock_limit)&&  perf_paranoid_tracepoint_raw()&&
>> 		!capable(CAP_IPC_LOCK)) {
>> 		ret = -EPERM;
>> 		goto unlock;
>> 	}
>>
>> So as long as you set perf_event_paranoid to -1 or run perf test as
>> root, you cannot see the failure.
>
> Ok, after this discussion, David, can I have your acked-by or tested-by?
>
> - Arnaldo

I had reviewed the whole series yesterday, so you can add my

Reviewed-by: David Ahern <dsahern@...il.com>

to the whole series if you want. I did not pull down the set and apply 
to test it, and this particular patch requires prior ones so I have not 
tested it.

David
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