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Date: Wed, 18 Nov 2015 11:51:04 +0900 From: Namhyung Kim <namhyung@...nel.org> To: Taeung Song <treeze.taeung@...il.com> CC: Arnaldo Carvalho de Melo <acme@...nel.org>, linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com> Subject: Re: [PATCH v11 10/24] perf config: Document variables for 'call-graph' section in man page On Tue, Nov 17, 2015 at 10:53:30PM +0900, Taeung Song wrote: > Explain 'call-graph' section and its variables. > > 'record-mode', 'dump-size', 'print-type', 'order', > 'sort-key', 'threshold' and 'print-limit'. > > Cc: Namhyung Kim <namhyung@...nel.org> > Cc: Jiri Olsa <jolsa@...hat.com> > Signed-off-by: Taeung Song <treeze.taeung@...il.com> > --- > tools/perf/Documentation/perf-config.txt | 65 ++++++++++++++++++++++++++++++++ > 1 file changed, 65 insertions(+) > > diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt > index 7d386d4..dc659d6 100644 > --- a/tools/perf/Documentation/perf-config.txt > +++ b/tools/perf/Documentation/perf-config.txt > @@ -285,6 +285,71 @@ ui.*:: > There're columns as header 'Overhead', 'Children', 'Shared Object', 'Symbol', 'self'. > If this option is false, they are hiden. 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) and 'dwarf'. Also 'lbr' can be used, but it only work for recent intel cpus. > + The value of 'dwarf' is effective only if perf detect needed library > + (libunwind or a recent version of libdw). Also it doesn't *require* > + the dump-size option since it can use the default value of 8192 if > + missing. I think the last sentence can be omitted. > + > + 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 this option should have a value. This contradicts the above, it'll use the default size if omitted. > + > + call-graph.print-type:: > + The print-types can be graph (graph absolute), fractal (graph relative), flat. > + 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 ^ it needs one more whitespace > + > + 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. > + > + 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 threashold. Default is 0.5 (%). s/threashold/threshold/ Also it'd be better to mention that the overhead is calculated by value depends on call-graph.print-type. > + > + call-graph.print-limit:: > + This is another way to control the number of callchains printed for a > + single entry. Default is 0 which means no limitation. This is a maximum number of lines of callchain printed for a single histogram entry. Thanks, Namhyung > + > SEE ALSO > -------- > linkperf:perf[1] > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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