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

From: Ingo Molnar
Date: Thu Oct 22 2015 - 04:23:18 EST



* Namhyung Kim <namhyung@xxxxxxxxxx> 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
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