From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Bram Stolk <b.stolk@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: Adding a recording delay interferes with symbols/call-stack
Date: Tue, 31 Oct 2017 11:25:37 -0300 [thread overview]
Message-ID: <20171031142537.GT7045@kernel.org> (raw)
In-Reply-To: <CABYXEksdehm6S9-WGO6MV1wQaWHCsk-Ofp-sDaxY+qwQSNPp8Q@mail.gmail.com>
Em Mon, Oct 30, 2017 at 01:25:08PM -0700, Bram Stolk escreveu:
> If I record with callstacks like this:
>
> $ perf record --freq 2000 --call-graph dwarf ./bench
>
> then it works just fine: I see callstacks, and symbols in the report.
>
> If I delay the recording by 1 second with the --delay flag, like this:
>
> $ perf record --delay=1000 --freq 2000 --call-graph dwarf ./bench
>
> Then I lose all callstack information, and even all symbol information
> on my program in the report.
>
> Is this a known issue, that --delay interferes with symbol resolution?
>
> Thanks!
>
> Bram
>
> PS: I am on 64b Ubuntu, and perf version 4.4.87
Works for me: :-)
[root@jouet ~]# perf record --delay=1000 --freq 2000 --call-graph dwarf sleep 5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.050 MB perf.data (4 samples) ]
[root@jouet ~]# perf script
perf 30567 248464.097254: 1 cycles:ppp:
3b233a __perf_event_task_sched_in (/lib/modules/4.14.0-rc3+/build/vmlinux)
2be207 finish_task_switch (/lib/modules/4.14.0-rc3+/build/vmlinux)
a44d21 __sched_text_start (/lib/modules/4.14.0-rc3+/build/vmlinux)
a45368 schedule (/lib/modules/4.14.0-rc3+/build/vmlinux)
a49679 do_nanosleep (/lib/modules/4.14.0-rc3+/build/vmlinux)
30c816 hrtimer_nanosleep (/lib/modules/4.14.0-rc3+/build/vmlinux)
30c96e sys_nanosleep (/lib/modules/4.14.0-rc3+/build/vmlinux)
203a41 do_syscall_64 (/lib/modules/4.14.0-rc3+/build/vmlinux)
a4ad67 return_from_SYSCALL_64 (/lib/modules/4.14.0-rc3+/build/vmlinux)
perf 30567 248464.097288: 1 cycles:ppp:
20d1d0 intel_bts_enable_local (/lib/modules/4.14.0-rc3+/build/vmlinux)
perf 30567 248464.097302: 3 cycles:ppp:
223111 native_sched_clock (/lib/modules/4.14.0-rc3+/build/vmlinux)
perf 30567 248464.097317: 16 cycles:ppp:
223111 native_sched_clock (/lib/modules/4.14.0-rc3+/build/vmlinux)
[root@jouet ~]# perf -v
perf version 4.14.rc6.gd688d0
[root@jouet ~]# uname -a
Linux jouet 4.14.0-rc3+ #1 SMP Fri Oct 13 12:21:12 -03 2017 x86_64 x86_64 x86_64 GNU/Linux
[root@jouet ~]#
next prev parent reply other threads:[~2017-10-31 14:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-30 20:25 Adding a recording delay interferes with symbols/call-stack Bram Stolk
2017-10-31 14:25 ` Arnaldo Carvalho de Melo [this message]
2017-10-31 17:10 ` Bram Stolk
2017-10-31 19:14 ` Arnaldo Carvalho de Melo
2017-11-01 4:36 ` Bram Stolk
2017-11-02 6:20 ` Namhyung Kim
2017-11-02 7:01 ` Bram Stolk
2017-11-02 7:07 ` Namhyung Kim
2017-11-02 7:10 ` Bram Stolk
2017-11-03 18:41 ` Arnaldo Carvalho de Melo
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