On Thursday, August 13, 2015 09:17:24 AM Jiri Olsa wrote: > 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?
<snip> Hey Jiri, it works a treat! Many thanks, much appreciated. -- Milian Wolff | milian.wo...@kdab.com | Software Engineer KDAB (Deutschland) GmbH&Co KG, a KDAB Group company Tel: +49-30-521325470 KDAB - The Qt Experts
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