From: Nikolay Borisov <kernel@kyup.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
andi@firstfloor.org
Subject: Re: Strange behavior of perf top with PEBS
Date: Wed, 20 Jul 2016 17:36:46 +0300 [thread overview]
Message-ID: <578F8C7E.9080503@kyup.com> (raw)
In-Reply-To: <20160720143417.GA25992@krava>
On 07/20/2016 05:34 PM, Jiri Olsa wrote:
> On Wed, Jul 20, 2016 at 04:28:34PM +0300, Nikolay Borisov wrote:
>> Hello,
>>
>> Running perf version 4.4.14.g0cb188d (no modification to the PMU/perf
>> code) I observed that "perf top" counts no cycles and produces no
>> output. After a bit of head scratching and testing I figured that
>> running "perf top -e cycles" actually works whereas the default option
>> is equivalent to running "perf top -e cycles:p". So the latter version
>> seems to not work on my machine.
>
> hum, I think Core2 has PEBs valid only for instructions not cycles..
FYI running perf top -e instructions:p also produces no data on that
particular CPU.
>
> I'll check why perf top forcing the precise for cycles
> I thought we had that automated already
>
> jirka
>
next prev parent reply other threads:[~2016-07-20 14:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 13:28 Strange behavior of perf top with PEBS Nikolay Borisov
2016-07-20 14:34 ` Jiri Olsa
2016-07-20 14:36 ` Nikolay Borisov [this message]
2016-07-20 14:38 ` Jiri Olsa
2016-07-26 11:30 ` Nikolay Borisov
2016-08-04 15:29 ` Jiri Olsa
2016-08-05 9:30 ` Nikolay Borisov
2016-08-05 10:23 ` Jiri Olsa
2016-08-08 13:03 ` Peter Zijlstra
2016-08-08 13:19 ` Greg Kroah-Hartman
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