From: Jiri Olsa <jolsa@redhat.com>
To: kan.liang@intel.com
Cc: acme@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com,
peterz@infradead.org, jolsa@kernel.org, adrian.hunter@intel.com,
andi@firstfloor.org
Subject: Re: [PATCH] perf tools: ignore zombie process for user profile
Date: Wed, 14 Dec 2016 18:59:11 +0100 [thread overview]
Message-ID: <20161214175911.GA14085@krava> (raw)
In-Reply-To: <1481737685-24595-1-git-send-email-kan.liang@intel.com>
On Wed, Dec 14, 2016 at 12:48:05PM -0500, kan.liang@intel.com wrote:
> From: Kan Liang <kan.liang@intel.com>
>
> If user has zombie process, the perf record -u will error out.
> Here is an example.
> $ ./testd &
> [1] 23796
> $ sudo perf record -e cycles -u kan
> Error:
> The sys_perf_event_open() syscall returned with 3 (No such process) for
> event (cycles).
> /bin/dmesg may provide additional information.
> No CONFIG_PERF_EVENTS=y kernel support configured?
>
> The source code of testd is as below.
> int main() {
>
> if (fork())
> {
> while (1);
> }
> return 0;
> }
>
> Zombie process is dead process. It is meaningless to profile it.
> It's better to ignore it for user profile.
I recently posted different patch for same issue:
http://marc.info/?l=linux-kernel&m=148153895827359&w=2
jirka
next prev parent reply other threads:[~2016-12-14 17:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-14 17:48 [PATCH] perf tools: ignore zombie process for user profile kan.liang
2016-12-14 17:59 ` Jiri Olsa [this message]
2016-12-14 18:26 ` Liang, Kan
2016-12-14 19:13 ` acme
2016-12-14 19:19 ` Liang, Kan
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