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authorGreg Price <price@MIT.EDU>2012-12-06 21:48:05 -0800
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-07-12 13:53:55 -0300
commitb21484f1a1f300d422cfe5d4f8f50015e22cea24 (patch)
tree145db22403268858a54a07db111464ff24b6818c /tools/perf/Documentation/perf-report.txt
parentdc098b35b56f83ae088e4291a4e389a6ff126965 (diff)
downloadlinux-b21484f1a1f300d422cfe5d4f8f50015e22cea24.tar.gz
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/perf-report.txt')
-rw-r--r--tools/perf/Documentation/perf-report.txt5
1 files changed, 5 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 66dab7410c1d..747ff50284b7 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