Re: buggy perf callgraph output

[Frederic Weisbecker]

On Thu, Dec 09, 2010 at 03:40:15AM +1100, Nick Piggin wrote:
> Hi,
> 
> I get strange looking perf output with the callchain hits not sorted
> properly for graph and fractal:
> 
>      7.34%          open  [kernel.kallsyms]     [k] kmem_cache_alloc
>                     |
>                     --- kmem_cache_alloc
>                        |          
>                        |---0.05%-- get_empty_filp
>                        |          do_filp_open
>                        |          do_sys_open
>                        |          sys_open
>                        |          system_call
>                        |          __open_nocancel
>                        |          
>                         ---0.16%-- getname
>                                   do_sys_open
>                                   sys_open
>                                   system_call
>                                   __open_nocancel
> 
>      6.17%          open  [kernel.kallsyms]     [k] _raw_spin_lock
>                     |
>                     --- _raw_spin_lock
>                        |          
>                        |---0.01%-- add_partial
>                        |          __slab_free
>                        |          kmem_cache_free
>                        |          file_free_rcu
>                        |          __rcu_process_callbacks
>                        |          rcu_process_callbacks
>                        |          __do_softirq
>                        |          call_softirq
>                        |          do_softirq
>                        |          irq_exit
>                        |          smp_apic_timer_interrupt
>                        |          apic_timer_interrupt
>                        |          
>                        |---0.16%-- dput
>                        |          |          
>                        |           --0.57%-- fput
>                        |                     filp_close
>                        |                     sys_close
>                        |                     system_call
>                        |                     __libc_close
>                        |          
>                        |--0.60%-- link_path_walk
>                        |          do_path_lookup
>                        |          do_filp_open
>                        |          do_sys_open
>                        |          sys_open
>                        |          system_call
>                        |          __open_nocancel
>                        |          
>                        |--0.57%-- __slab_free
>                        |          kmem_cache_free
>                        |          file_free_rcu
>                        |          __rcu_process_callbacks
>                        |          rcu_process_callbacks
>                        |          __do_softirq
> 
> 
> With flat it looks a bit better:
>      7.34%          open  [kernel.kallsyms]     [k] kmem_cache_alloc
>              6.09%
>                 kmem_cache_alloc
>                 get_empty_filp
>                 do_filp_open
>                 do_sys_open
>                 sys_open
>                 system_call
>                 __open_nocancel
> 
>              1.07%
>                 kmem_cache_alloc
>                 getname
>                 do_sys_open
>                 sys_open
>                 system_call
>                 __open_nocancel
> 
>      6.17%          open  [kernel.kallsyms]     [k] _raw_spin_lock
>              0.60%
>                 _raw_spin_lock
>                 link_path_walk
>                 do_path_lookup
>                 do_filp_open
>                 do_sys_open
>                 sys_open
>                 system_call
>                 __open_nocancel
> 
>              0.57%
>                 _raw_spin_lock
>                 fd_install
>                 do_sys_open
>                 sys_open
>                 system_call
>                 __open_nocancel
> 
>              0.57%
>                 _raw_spin_lock
>                 dput
>                 fput
>                 filp_close
>                 sys_close
>                 system_call
>                 __libc_close


I can not reproduce it. Could you please try to reproduce,
run perf archive and send me your perf.data.tar.bz2 ?

Thanks.
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