linux-kernel - Re: [PATCH v3] perf/trace : Fix repetitious traces of perf on tracepoint

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Message-ID: <20180117142553.GA13639@kernel.org>
Date:   Wed, 17 Jan 2018 11:25:53 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Cheng Jian <cj.chengjian@...wei.com>
Cc:     Jiri Olsa <jolsa@...hat.com>, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        namhyung@...nel.org, xiexiuqi@...wei.com, huawei.libin@...wei.com,
        wangnan0@...wei.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] perf/trace : Fix repetitious traces of perf on
 tracepoint

Em Wed, Jan 17, 2018 at 10:33:42AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Jan 16, 2018 at 04:06:22PM +0100, Jiri Olsa escreveu:
> > On Tue, Jan 16, 2018 at 08:40:38PM +0800, Cheng Jian wrote:
> > > after this patch, perf script(parent-1040, child-1041):

> > > 	test_fork  1040 [002]    36.536079: sched:sched_wakeup_new: comm=test_fork pid=1041 prio=120 target_cpu=003

> > > It will match it only once for tracing task(child-1041).

> > > Signed-off-by: Cheng Jian <cj.chengjian@...wei.com>

> > the duplicated events are gone.. solution looks ok to me

> > Reviewed-and-Tested-by: Jiri Olsa <jolsa@...nel.org>

> I noticed that in the past as well, will try to test this too.

Unpatched kernel:

[root@...et ~]# perf trace --no-syscalls -e sched:sched_wakeup_new time sleep 1
     0.000 sched:sched_wakeup_new:time:13571 [120] success=1 CPU:003)
18446744073709.547 sched:sched_wakeup_new:time:13571 [120] success=1 CPU:003)
18446744073709.551 sched:sched_wakeup_new:time:13571 [120] success=1 CPU:003)
18446744073709.551 sched:sched_wakeup_new:time:13571 [120] success=1 CPU:003)
18446744073709.551 sched:sched_wakeup_new:time:13571 [120] success=1 CPU:003)
0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 1996maxresident)k
0inputs+0outputs (0major+71minor)pagefaults 0swaps
[root@...et ~]# 

Patched kernel:

[root@...enth ~]# perf trace --no-syscalls -e sched:sched_wakeup_new time sleep 1
     0.000 sched:sched_wakeup_new:comm=time pid=339 prio=120 target_cpu=002)
     0.001 sched:sched_wakeup_new:comm=time pid=339 prio=120 target_cpu=002)
0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 2084maxresident)k
0inputs+0outputs (0major+75minor)pagefaults 0swaps
[root@...enth ~]#