linux-kernel - Re: perf script doesn't dump a normal call trace

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Date:   Tue, 6 Nov 2018 17:22:13 +0900
From:   Xin Long <lucien.xin@...il.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>
Subject: Re: perf script doesn't dump a normal call trace

On Mon, Nov 5, 2018 at 5:49 PM Jiri Olsa <jolsa@...hat.com> wrote:
>
> On Mon, Nov 05, 2018 at 03:20:15PM +0900, Xin Long wrote:
>
> SNIP
>
> > > > > [root@...-x3650m4-02 perf]# ./perf probe 'consume_skb'
> > > > > [root@...-x3650m4-02 perf]# ./perf record -g -e probe:consume_skb* -aR ^C
> > > > >
> > > > Thanks Jiri,
> > > >
> > > > My debugging script is using tracepoint with some filters which I
> > > > don't think probe can support.
> > > > Any one have fixes for this tracepoint issue?
> > >
> > > trying to bisect that.. looks like orc code issue,
> > > it works for me when you switch to fp unwind:
> > >   CONFIG_UNWINDER_FRAME_POINTER
> > >
> >
> > That's a good workaround, thanks.
> >
> > Another problem is when I'm using perf built manually from upstream kernel tree,
> > I couldn't see the function's names.
> > # perf --version
> > perf version 4.19.g26f1de
> >
> > # perf report -T
> > # To display the perf.data header info, please use
> > --header/--header-only options.
> > #
> > #
> > # Total Lost Samples: 0
> > #
> > # Samples: 97  of event 'probe:consume_skb'
> > # Event count (approx.): 97
> > #
> > # Children      Self  Trace output
> > # ........  ........  ..................
> > #
> >    100.00%   100.00%  (ffffffff86f090f0)
> >             |
> >             |--93.81%--0xffffffff868000e6
> >             |          0xffffffff8684ed7f
> >             |          0xffffffff868e97ad
> >             |          0xffffffff868e953a
> >             |          0xffffffff87087623
> >             |          0xffffffff8682a06f
> >             |          0xffffffff870872ad
> >             |          |
> >             |          |--89.69%--0xffffffff8720098f
> >             |          |          0xffffffff87201b69
> >             |          |          0xffffffff868b9c2e
> >
> >
> > The below is with rhel7's perf
> > # perf --version
> > perf version 3.10.0-957.el7.x86_64.debug
> > # perf report -T
> > # To display the perf.data header info, please use
> > --header/--header-only options.
> > #
> > #
> > # Total Lost Samples: 0
> > #
> > # Samples: 97  of event 'probe:consume_skb'
> > # Event count (approx.): 97
> > #
> > # Children      Self  Trace output
> > # ........  ........  ..................
> > #
> >    100.00%   100.00%  (ffffffff86f090f0)
> >             |
> >             |--93.81%--0x2000e6
> >             |          start_secondary
> >             |          cpu_startup_entry
> >             |          do_idle
> >             |          default_idle_call
> >             |          arch_cpu_idle
> >             |          default_idle
> >             |          |
> >             |          |--89.69%--ret_from_intr
> >             |          |          do_IRQ
> >             |          |          irq_exit
>
> I think that's already fixed on Arnaldo's perf/urgent branch,
>   git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git
>
> but perhaps this post as well:
>   https://lore.kernel.org/lkml/20181031091043.23465-1-adrian.hunter@intel.com/
>
> please give it a try.. it should be merged in soon
I will try it later, I have another question?
# perf report -T

# Samples: 97  of event 'probe:consume_skb'
# Event count (approx.): 97
#
# Children      Self  Trace output
# ........  ........  ..................
#
   100.00%   100.00%  (ffffffff86f090f0)
            |
            |--93.81%--0x2000e6
            |          start_secondary
            |          cpu_startup_entry
            |          do_idle
            |          default_idle_call
            |          arch_cpu_idle
          [...]
            |          |                     |
            |          |                      --2.06%--arp_process
            |          |                                neigh_update
            |          |                                __neigh_notify
            |          |                                rtnl_notify
            |          |                                nlmsg_notify
            |          |                                consume_skb  <-----[1]


This command can show a nice tree, and it has the total samples number 97.
But I couldn't see how many of them are from [1]?
Do you know how to count each path's numbers?
Is there an option for "perf report" to do these statistics?
Thanks.