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| author | Greg Price <price@MIT.EDU> | 2012-12-07 05:48:05 (GMT) |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2013-07-12 16:53:55 (GMT) |
| commit | b21484f1a1f300d422cfe5d4f8f50015e22cea24 (patch) | |
| tree | 145db22403268858a54a07db111464ff24b6818c /tools/perf/Documentation | |
| parent | dc098b35b56f83ae088e4291a4e389a6ff126965 (diff) | |
| download | linux-b21484f1a1f300d422cfe5d4f8f50015e22cea24.tar.xz | |
perf report/top: Add option to collapse undesired parts of call graph
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: Greg Price <price@mit.edu>
Tested-by: Jiri 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: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-report.txt | 5 | ||||
| -rw-r--r-- | tools/perf/Documentation/perf-top.txt | 5 |
2 files changed, 10 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt index 66dab74..747ff50 100644 --- a/tools/perf/Documentation/perf-report.txt +++ b/tools/perf/Documentation/perf-report.txt @@ -135,6 +135,11 @@ OPTIONS --inverted:: alias for inverted caller based call graph. +--ignore-callees=<regex>:: + Ignore callees of the function(s) matching the given regex. + This has the effect of collecting the callers of each such + function into one place in the call-graph tree. + --pretty=<key>:: Pretty printing style. key: normal, raw diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt index 7fdd190..58d6598 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -155,6 +155,11 @@ Default is to monitor all CPUS. Default: fractal,0.5,callee. +--ignore-callees=<regex>:: + Ignore callees of the function(s) matching the given regex. + This has the effect of collecting the callers of each such + function into one place in the call-graph tree. + --percent-limit:: Do not show entries which have an overhead under that percent. (Default: 0). |