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    SubjectRe: [PATCH v11 10/24] perf config: Document variables for 'call-graph' section in man page
    On Mon, Nov 30, 2015 at 10:42:00AM +0900, Taeung Song wrote:
    > Hi, Namhyung

    Hi Taeung,

    > > On Nov 18, 2015, at 11:51 AM, Namhyung Kim <namhyung@kernel.org> wrote:
    > >
    > > 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@kernel.org>
    > >> Cc: Jiri Olsa <jolsa@redhat.com>
    > >> Signed-off-by: Taeung Song <treeze.taeung@gmail.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.

    The 'folded' print type was added recently. Please update it too.


    > >> + 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
    > >
    >
    > I checked this patch file and whitespace and tab characters on it.
    > But I think the lacking whitespace because of mail client.
    > After 'make install’ I checked it but there is no lack of whitespace.
    > Are there different problems that I missed ?

    I meant whitespace in the callchain graph (i.e. 'bar' and 'baz' should
    be aligned). But I think I was wrong - it should look like below:


    Overhead Symbols
    ........ .......
    40.00% foo
    |
    ---foo
    |
    |--50.00%--bar
    | main
    |
    --50.00%--baz
    main


    Maybe it's because you used TAB characters for indent?

    Thanks,
    Namhyung


    >
    > >
    > >> +
    > >> + 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
    >


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