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From: Jiri Olsa <jolsa@redhat.com>
To: Raghavendra Rao Ananta <rananta@codeaurora.org>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	alexander.shishkin@linux.intel.com, namhyung@kernel.org,
	linux-kernel@vger.kernel.org, psodagud@codeaurora.org,
	tsoni@codeaurora.org
Subject: Re: [PATCH] perf: Add support for creating offline events
Date: Mon, 12 Feb 2018 22:04:42 +0100	[thread overview]
Message-ID: <20180212210442.GA32093@krava> (raw)
In-Reply-To: <53408020-8638-4947-90f6-87dbc4c2c4e5@codeaurora.org>

On Mon, Feb 12, 2018 at 09:42:05AM -0800, Raghavendra Rao Ananta wrote:
> Hi Jiri,
> 
> Thank you for the response.
> 
> Does perf tool has its own check to see if the CPU was offline during the
> lifetime of an event? If so, it might ignore these type of events.

nope, we don't check on that

> 
> Initially, I tested the same using perf tool and found similar results.
> Then I debugged further and found that the perf core was actually sending
> data to the userspace (copy_to_user()) and the corresponding count for the
> data. Hence, I tested this further by writing my own userspace application,
> and I was able to read the count through this,
> even when the CPU was made offline and back online.
> 
> Do you think we also have to modify the perf tool accordingly?

hum, I wonder what's wrong.. will check

jirka

  reply	other threads:[~2018-02-12 21:04 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-09 23:07 [PATCH] perf: Add support for creating offline events Raghavendra Rao Ananta
2018-02-12  9:43 ` Jiri Olsa
2018-02-12 17:42   ` Raghavendra Rao Ananta
2018-02-12 21:04     ` Jiri Olsa [this message]
2018-02-12 21:21       ` Jiri Olsa
2018-02-12 22:22         ` Raghavendra Rao Ananta
2018-02-13 16:08           ` Jiri Olsa
2018-02-13 18:03             ` Raghavendra Rao Ananta
2018-02-12  9:44 ` Jiri Olsa
2018-02-12 19:11 ` kbuild test robot
2018-02-13 18:23 ` Peter Zijlstra
2018-02-13 22:17   ` Sodagudi Prasad
2018-02-14  8:32     ` Peter Zijlstra

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