Re: [PATCH 2/3] perf top: Support call-graph display options also

[Ingo Molnar <mingo@kernel.org>]

* Namhyung Kim <namhyung@kernel.org> wrote:

> Currently 'perf top --call-graph' option is same as 'perf record'.  But
> 'perf top' also need to receive display options in 'perf report'.  To do
> that, change parse_callchain_report_opt() to allow record options too.
> 
> Now perf top can receive display options like below:
> 
>   $ perf top --call-graph
>     Error: option `call-graph' requires a value
> 
>    Usage: perf top [<options>]
> 
>         --call-graph
>           <mode[,dump_size],output_type,min_percent[,print_limit],call_order[,branch]>
>                      setup and enables call-graph (stack chain/backtrace)
>                      recording: fp dwarf lbr, output_type (graph, flat,
> 		     fractal, or none), min percent threshold, optional
> 		     print limit, callchain order, key (function or
> 		     address), add branches

Yeah, so this fix is nice, and I think we should also do another patch to fix the 
help text output to be the following:

         --call-graph
           <record_mode[,record_size],print_style,limit[,print_limit],call_order[,sort_key]>

              Set up and enable call graph (call chain, stack backtrace) recording:

                 record_mode:   call graph recording mode (fp|dwarf|lbr)
                 record_size:   if rec_mode == dwarf, maximum depth of stack recording (bytes),
                                default: 8192 bytes.
                 print_style:   call graph printing style (graph|flat|fractal|none)
                 limit:         minimum call graph inclusion threshold (percent)
                 print_limit:   printing threshold (percent)
                 call_order:    call graph order (caller|callee)
                 sort_key:      sorting key (function|address|branch)

               Default: fp,graph,0.5,0.0,caller,function

Note that this text evolved a bit over what I sent in my previous mail.

Also note that I think we should sync up the perf config options to be the same as 
the option name shortcuts used in this help text.

Side note: to improve perf config usability, we should probably also recognize 
underscores in perf config entries, i.e. the following variants should both work:

	print_percent = 1
	print-percent = 1

Right now only the second one will match.

Thanks,

	Ingo