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From: Ingo Molnar <mingo@kernel.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Wang Nan <wangnan0@huawei.com>, Ingo Molnar <mingo@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	He Kuang <hekuang@huawei.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Brendan Gregg <brendan.d.gregg@gmail.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Namhyung Kim <namhyung@kernel.org>, Zefan Li <lizefan@huawei.com>,
	pi3orama@163.com
Subject: Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer
Date: Tue, 8 Mar 2016 18:57:53 +0100	[thread overview]
Message-ID: <20160308175753.GA3015@gmail.com> (raw)
In-Reply-To: <20160308174856.GA28862@gmail.com>


* Ingo Molnar <mingo@kernel.org> wrote:

> Things got a lot more lively after that!
> 
> But most of the overhead seems to come from systemd trying to dump core or 
> something like that:
> 
>  85872 mingo     20   0   34712   3016   2656 S   4.6  0.0   0:00.14 systemd-coredum                                                                                                  
>  85440 mingo     20   0   34712   3028   2664 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85751 mingo     20   0   34712   3076   2716 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85840 mingo     20   0   34712   2988   2624 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85861 mingo     20   0   34712   3080   2720 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85954 mingo     20   0   34712   3028   2664 S   4.2  0.0   0:00.13 systemd-coredum          
> 
> and I have:
> 
>  fomalhaut:~/go/src/github.com/google/syzkaller> ulimit -c
>  0
> 
> weird ... Has any of you seen such behavior?

So the workaround for that is to disable systemd trying to log every core dump to 
the system journal (!), via:

  echo > /proc/sys/kernel/core_pattern 

Thanks,

	Ingo

  parent reply	other threads:[~2016-03-08 17:58 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-07  3:50 [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Wang Nan
2016-03-07  3:50 ` [RESEND PATCH 1/5] perf core: Introduce new ioctl options to pause and resume " Wang Nan
2016-03-07  3:50 ` [RESEND PATCH 2/5] perf core: Set event's default overflow_handler Wang Nan
2016-03-07  3:50 ` [RESEND PATCH 3/5] perf core: Prepare writing into ring buffer from end Wang Nan
2016-03-07  3:50 ` [RESEND PATCH 4/5] perf core: Add backward attribute to perf event Wang Nan
2016-03-07  3:50 ` [RESEND PATCH 5/5] perf core: Reduce perf event output overhead by new overflow handler Wang Nan
2016-03-08 13:44 ` [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra
2016-03-08 13:49   ` Ingo Molnar
2016-03-08 13:57     ` Peter Zijlstra
2016-03-08 15:29       ` Ingo Molnar
2016-03-08 15:35         ` Dmitry Vyukov
2016-03-08 15:54           ` Ingo Molnar
2016-03-08 16:11             ` Dmitry Vyukov
2016-03-08 16:27               ` Ingo Molnar
2016-03-08 16:29                 ` Dmitry Vyukov
2016-03-08 16:32                   ` Peter Zijlstra
2016-03-08 16:44                   ` Ingo Molnar
2016-03-08 16:48                     ` Ingo Molnar
2016-03-08 16:59                       ` Dmitry Vyukov
2016-03-08 17:24                         ` Ingo Molnar
2016-03-08 17:27                           ` Dmitry Vyukov
2016-03-08 17:37                             ` Ingo Molnar
2016-03-08 17:41                               ` Dmitry Vyukov
2016-03-08 17:48                                 ` Ingo Molnar
2016-03-08 17:56                                   ` Dmitry Vyukov
2016-03-08 17:56                                   ` Peter Zijlstra
2016-03-08 17:57                                   ` Ingo Molnar [this message]
2016-03-08 18:02                                     ` Ingo Molnar
2016-03-08 18:22                                       ` Ingo Molnar
2016-03-08 18:31                                         ` Ingo Molnar
2016-03-08 17:55                               ` Peter Zijlstra
2016-03-08 16:30                 ` Peter Zijlstra
2016-03-09 10:53             ` Borislav Petkov
2016-03-09 11:19               ` Dmitry Vyukov
2016-03-08 19:56       ` Jiri Olsa
2016-03-08 20:07         ` Peter Zijlstra
2016-03-08 20:44           ` Jiri Olsa
2016-03-08 21:04             ` Peter Zijlstra

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