From 56c94dc56f9e4c1c09fbe26ad65715caa2259438 Mon Sep 17 00:00:00 2001 From: Taeung Song Date: Thu, 4 Feb 2016 18:25:07 +0900 Subject: [PATCH] perf config: Document variables for 'call-graph' section in man page 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 Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/1454577913-16401-3-git-send-email-treeze.taeung@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 42787222ad15..42310ae7e636 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] -- 2.20.1