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Subject[PATCH 2/8] perf config: Document variables for 'call-graph' section in man page
Date
Explain 'call-graph' section and its variables.

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

Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
---
tools/perf/Documentation/perf-config.txt | 67 ++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 4278722..42310ae 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -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]
--
2.5.0
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