From eadcaa3dfd706bbf46682c8b8b5979262443c3c3 Mon Sep 17 00:00:00 2001 From: Tony Jones Date: Wed, 25 Mar 2020 09:40:53 -0700 Subject: perf callchain: Update docs regarding kernel/user space unwinding The method of unwinding for kernel space is defined by the kernel config, not by the value of --call-graph. Improve the documentation to reflect this. Signed-off-by: Tony Jones Link: http://lore.kernel.org/lkml/20200325164053.10177-1-tonyj@suse.de Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-config.txt | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'tools/perf/Documentation/perf-config.txt') diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt index 8ead55593984..f16d8a71d3f5 100644 --- a/tools/perf/Documentation/perf-config.txt +++ b/tools/perf/Documentation/perf-config.txt @@ -405,14 +405,16 @@ ui.*:: 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. + The following controls the handling of call-graphs (obtained via the + -g/--call-graph options). 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. + The mode for user space can be 'fp' (frame pointer), 'dwarf' + and 'lbr'. The value 'dwarf' is effective only if libunwind + (or a recent version of libdw) is present on the system; + the value 'lbr' only works for certain cpus. The method for + kernel space is controlled not by this option but by the + kernel config (CONFIG_UNWINDER_*). call-graph.dump-size:: The size of stack to dump in order to do post-unwinding. Default is 8192 (byte). -- cgit v1.2.3