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 <m...@milianw.de> Link: http://lkml.kernel.org/n/tip-vtgxy0tv3gogvomyhc2c5...@git.kernel.org Signed-off-by: Jiri Olsa <jo...@kernel.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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
