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Message-ID: <20150813071724.GA21322@krava.brq.redhat.com>
Date: Thu, 13 Aug 2015 09:17:24 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Milian Wolff <mail@...ianw.de>
Cc: Perf Users <linux-perf-users@...r.kernel.org>,
lkml <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: [PATCH] perf script: Initialize callchain_param.record_mode
On Wed, Jul 22, 2015 at 08:48:40PM +0200, Milian Wolff wrote:
> Hey all,
>
> I recorded a perf data file using
>
> perf record --call-graph dwarf kwrite <some large file>
>
> when I report it I see backtraces pointing to the user space code:
>
> perf report --stdio -g graph --no-children
> 16.36% kwrite libKF5TextEditor.so.5.13.0 [.]
> QArrayData::data
> |
> ---QArrayData::data
> |
> |--15.46%-- QTypedArrayData<unsigned short>::data
>
> but when I run perf script, I do not see _any_ backtraces into user space.
>
> perf script -F comm,tid,time,event,ip,sym,trace,period
> :4898 4898 17486.943365: 1 cycles:
> 25f83a native_write_msr_safe
> 234f8a __intel_pmu_enable_all
> 235010 intel_pmu_enable_all
> 22e1ec x86_pmu_enable
> 356fb7 perf_pmu_enable.part.53
> 35824d perf_event_context_sched_in.isra.64
> 358e0b perf_event_exec
> 3e8c93 setup_new_exec
> 439a9f load_elf_binary
> 3e7f48 search_binary_handler
> 3e89cf do_execveat_common.isra.15
> 3e8e4a sys_execve
> 78b895 return_from_execve
>
> kwrite 4898 17486.943893: 1 cycles:
> kwrite 4898 17486.944211: 1 cycles:
> ...
> kwrite 4898 17486.953664: 461703 cycles:
> kwrite 4898 17486.953838: 490150 cycles:
> 78d4c0 page_fault
> kwrite 4898 17486.954009: 516694 cycles:
> ...
> kwrite 4898 17510.765568: 766937 cycles:
> 78979b down_write
> 39bd82 unlink_file_vma
> 3944d0 free_pgtables
> 39eef6 exit_mmap
> 275d45 mmput
> 27b514 do_exit
> 27bdfb do_group_exit
> 27be84 [unknown]
> 78b56e system_call
>
> So it looks to me as if only kernel-space call stacks are unwound in perf
> script. Is there a magic switch that I'm missing to get user-space stacks
> unwound? Note I'm using perf 4.1.0 on a Linux 4.1.2 system.
hi,
right you are.. does attached patch help?
thanks,
jirka
---
Milian Wolff reported non functional DWARF unwind under perf
script. The reason is that perf script does not properly configure
callchain_param.record_mode, which is needed by unwind code.
Stealing the code from report and leaving the place for
more initialization code in a hope we could merge it with
report__setup_sample_type one day.
Reported-by: Milian Wolff <mail@...ianw.de>
Link: http://lkml.kernel.org/n/tip-vtgxy0tv3gogvomyhc2c50rm@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
tools/perf/builtin-script.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 7b376d215e94..105332e950a9 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1561,6 +1561,22 @@ static int have_cmd(int argc, const char **argv)
return 0;
}
+static void script__setup_sample_type(struct perf_script *script)
+{
+ struct perf_session *session = script->session;
+ u64 sample_type = perf_evlist__combined_sample_type(session->evlist);
+
+ if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
+ if ((sample_type & PERF_SAMPLE_REGS_USER) &&
+ (sample_type & PERF_SAMPLE_STACK_USER))
+ callchain_param.record_mode = CALLCHAIN_DWARF;
+ else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+ callchain_param.record_mode = CALLCHAIN_LBR;
+ else
+ callchain_param.record_mode = CALLCHAIN_FP;
+ }
+}
+
int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
{
bool show_full_info = false;
@@ -1849,6 +1865,7 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
goto out_delete;
script.session = session;
+ script__setup_sample_type(&script);
session->itrace_synth_opts = &itrace_synth_opts;
--
2.4.3
--
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