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perf config: Document variables for 'call-graph' section in man page

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Explain 'call-graph' section and its variables:

  'record-mode', 'dump-size', 'print-type', 'order', 'sort-key',
  'threshold' and 'print-limit'.

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1454577913-16401-3-git-send-email-treeze.taeung@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Taeung Song 2016-02-04 18:25:07 +09:00 committed by Arnaldo Carvalho de Melo
parent 67f43c0097
commit 56c94dc56f
1 changed files with 67 additions and 0 deletions
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67
tools/perf/Documentation/perf-config.txt
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@ -302,6 +302,73 @@ ui.*::
in 'report' and 'top'. If this option is false, they are hidden.
This option is only applied to TUI.
call-graph.*::
When sub-commands 'top' and 'report' work with -g/—-children
there're options in control of call-graph.
call-graph.record-mode::
The record-mode can be 'fp' (frame pointer), 'dwarf' and 'lbr'.
The value of 'dwarf' is effective only if perf detect needed library
(libunwind or a recent version of libdw).
'lbr' only work for cpus that support it.
call-graph.dump-size::
The size of stack to dump in order to do post-unwinding. Default is 8192 (byte).
When using dwarf into record-mode, the default size will be used if omitted.
call-graph.print-type::
The print-types can be graph (graph absolute), fractal (graph relative),
flat and folded. This option controls a way to show overhead for each callchain
entry. Suppose a following example.
Overhead Symbols
........ .......
40.00% foo
|
---foo
|
|--50.00%--bar
| main
|
--50.00%--baz
main
This output is a 'fractal' format. The 'foo' came from 'bar' and 'baz' exactly
half and half so 'fractal' shows 50.00% for each
(meaning that it assumes 100% total overhead of 'foo').
The 'graph' uses absolute overhead value of 'foo' as total so each of
'bar' and 'baz' callchain will have 20.00% of overhead.
If 'flat' is used, single column and linear exposure of call chains.
'folded' mean call chains are displayed in a line, separated by semicolons.
call-graph.order::
This option controls print order of callchains. The default is
'callee' which means callee is printed at top and then followed by its
caller and so on. The 'caller' prints it in reverse order.
If this option is not set and report.children or top.children is
set to true (or the equivalent command line option is given),
the default value of this option is changed to 'caller' for the
execution of 'perf report' or 'perf top'. Other commands will
still default to 'callee'.
call-graph.sort-key::
The callchains are merged if they contain same information.
The sort-key option determines a way to compare the callchains.
A value of 'sort-key' can be 'function' or 'address'.
The default is 'function'.
call-graph.threshold::
When there're many callchains it'd print tons of lines. So perf omits
small callchains under a certain overhead (threshold) and this option
control the threshold. Default is 0.5 (%). The overhead is calculated
by value depends on call-graph.print-type.
call-graph.print-limit::
This is a maximum number of lines of callchain printed for a single
histogram entry. Default is 0 which means no limitation.
SEE ALSO
--------
linkperf:perf[1]