• Greg Price's avatar
    perf report/top: Add option to collapse undesired parts of call graph · b21484f1
    Greg Price authored
    For example, in an application with an expensive function implemented
    with deeply nested recursive calls, the default call-graph presentation
    is dominated by the different callchains within that function.  By
    ignoring these callees, we can collect the callchains leading into the
    function and compactly identify what to blame for expensive calls.
    
    For example, in this report the callers of garbage_collect() are
    scattered across the tree:
    
      $ perf report -d ruby 2>- | grep -m10 ^[^#]*[a-z]
          22.03%     ruby  [.] gc_mark
                     --- gc_mark
                        |--59.40%-- mark_keyvalue
                        |          st_foreach
                        |          gc_mark_children
                        |          |--99.75%-- rb_gc_mark
                        |          |          rb_vm_mark
                        |          |          gc_mark_children
                        |          |          gc_marks
                        |          |          |--99.00%-- garbage_collect
    
    If we ignore the callees of garbage_collect(), its callers are coalesced:
    
      $ perf report --ignore-callees garbage_collect -d ruby 2>- | grep -m10 ^[^#]*[a-z]
          72.92%     ruby  [.] garbage_collect
                     --- garbage_collect
                         vm_xmalloc
                        |--47.08%-- ruby_xmalloc
                        |          st_insert2
                        |          rb_hash_aset
                        |          |--98.45%-- features_index_add
                        |          |          rb_provide_feature
                        |          |          rb_require_safe
                        |          |          vm_call_method
    Signed-off-by: default avatarGreg Price <price@mit.edu>
    Tested-by: default avatarJiri Olsa <jolsa@redhat.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Link: http://lkml.kernel.org/r/20130623031720.GW22203@biohazard-cafe.mit.edu
    Link: http://lkml.kernel.org/r/20130708115746.GO22203@biohazard-cafe.mit.edu
    Cc: Fengguang Wu <fengguang.wu@intel.com>
    [ remove spaces at beginning of line, reported by Fengguang Wu ]
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    b21484f1
machine.c 29.5 KB