Messages in this thread | | | Subject | Re: [PATCH] perf tools: update docs regarding kernel/user space unwinding | From | Paul Clarke <> | Date | Thu, 26 Mar 2020 16:32:26 -0500 |
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On 3/25/20 11:40 AM, Tony Jones wrote: > 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.
> diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt > index 8ead55593984..88cf35fbedc5 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/--callgraph 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_*).
Your changes are just copying the old text, so this isn't a criticism of your patches.
Do we have information to replace "a recent version of libdw", which will quickly get stale?
PC
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