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Date:	Fri, 9 Oct 2015 13:34:33 -0700
From:	Brendan Gregg <brendan.d.gregg@...il.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Borislav Petkov <bp@...e.de>,
	Chandler Carruth <chandlerc@...il.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Stephane Eranian <eranian@...gle.com>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH 13/16] perf callchain: Switch default to 'graph,0.5,caller'

On Mon, Oct 5, 2015 at 2:03 PM, Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> Which is the most common default found in other similar tools.


Interactive tools, sure, like the perf report TUI.

But this also changes the ordering of the non-interactive tools which
dump stacks: "perf report -n --stdio" and "perf script". The most
common default for dumping stacks is caller. Eg:

# perf report -n --stdio
[...]
    16.87%        334           iperf  [kernel.kallsyms]     [k]
copy_user_enhanced_fast_string
                     |
                     --- 0x7f0683ba1ccd
                         system_call_fastpath
                         sys_write
                         vfs_write
                         do_sync_write
                         sock_aio_write
                         do_sock_write.isra.10
                         inet_sendmsg
                         copy_user_enhanced_fast_string
[...]

That's upside down. The current default preserves ordering from the
informational line onwards:

# perf report -n --stdio -g fractal,0.5,callee
[...]
    16.87%        334           iperf  [kernel.kallsyms]     [k]
copy_user_enhanced_fast_string
                     |
                     --- copy_user_enhanced_fast_string
                        |
                        |--64.37%-- inet_sendmsg
                        |          do_sock_write.isra.10
                        |          sock_aio_write
                        |          do_sync_write
                        |          vfs_write
                        |          sys_write
                        |          system_call_fastpath
                        |          0x7f0683ba1ccd

... Those are just short examples. Another profile I'm working on now
gets really messy on "perf report -n --stdio"; eg:

perf report -n --stdio -g graph,0.5,caller
    94.80%     0.10%             2  iperf     [kernel.vmlinux]    [k]
entry_SYSCALL_64_fastpath
               |
               |--94.70%-- entry_SYSCALL_64_fastpath
               |          |
               |          |--55.76%-- sys_write
               |          |          |
               |          |          |--55.10%-- vfs_write
               |          |          |          |
               |          |          |          |--54.39%-- __vfs_write
               |          |          |          |          |
               |          |          |          |           --54.34%--
sock_write_iter
               |          |          |          |                     |
               |          |          |          |
|--54.19%-- sock_sendmsg
               |          |          |          |
|          |
               |          |          |          |
|          |--53.99%-- inet_sendmsg
               |          |          |          |
|          |          |
               |          |          |          |
|          |          |--53.08%-- tcp_sendmsg
               |          |          |          |
|          |          |          |
               |          |          |          |
|          |          |          |--17.27%--
copy_user_enhanced_fast_string
               |          |          |          |
|          |          |          |
               |          |          |          |
|          |          |          |--11.41%-- tcp_push_one
               |          |          |          |
|          |          |          |          |
               |          |          |          |
|          |          |          |          |--11.31%-- tcp_write_xmit
               |          |          |          |
|          |          |          |          |          |
               |          |          |          |
|          |          |          |          |          |--10.00%--
tcp_transmit_skb
               |          |          |          |
|          |          |          |          |          |          |
               |          |          |          |
|          |          |          |          |          |
|--9.29%-- ip_queue_xmit
               |          |          |          |
|          |          |          |          |          |          |
      |
               |          |          |          |
|          |          |          |          |          |          |
      |--8.69%-- ip_local_out_sk
               |          |          |          |
|          |          |          |          |          |          |
      |          |
               |          |          |          |
|          |          |          |          |          |          |
      |          |--8.64%-- ip_output
               |          |          |          |
|          |          |          |          |          |          |
      |          |          ip_finish_output
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |--8.43%-- ip_finish_output2
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |--6.97%-- __local_bh_enable_ip
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |--6.82%--
do_softirq
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |          |
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |
--6.77%-- do_softirq_own_stack
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |
 |
               |          |          |          |
|          |          |          |          |          |          |
      |          |          |          |          |
 |--6.46%-- __do_softirq
[...]

The current default never gets beyond 5 levels deep. The new default
goes to 25 levels. At least with perf report I can override the
default using "-g". perf script doesn't support that.

Can this patch please preserve the callee ordering for non-interactive
output? (perf script, perf report -n --stdio). Thanks,

Brendan
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