Re: [PATCH] perf report: Add warning when libunwind not compiled in

From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Jin Yao <yao.jin@linux.intel.com>
Cc: jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com,
	alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org,
	ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com
Subject: Re: [PATCH] perf report: Add warning when libunwind not compiled in
Date: Mon, 14 Oct 2019 11:13:04 -0300	[thread overview]
Message-ID: <20191014141304.GE19627@kernel.org> (raw)
In-Reply-To: <20191011022122.26369-1-yao.jin@linux.intel.com>

Em Fri, Oct 11, 2019 at 10:21:22AM +0800, Jin Yao escreveu:
> We received a user report that call-graph dwarf mode was enabled in perf
> record but perf report didn't unwind the callstack correctly. The reason was,
> libunwind was not compiled in.
> 
> We can use 'perf -vv' to check the compiled libraries but it would be valuable
> to report a warning to user directly (especially valuable for perf newbie).
> 
> The warning is,
> 
> Warning:
> Please install libunwind development packages during the perf build.
> 
> Both tui and stdio are supported.

Thanks, applied.

> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> ---
>  tools/perf/builtin-report.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index aae0e57c60fb..7accaf8ef689 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -399,6 +399,13 @@ static int report__setup_sample_type(struct report *rep)
>  				PERF_SAMPLE_BRANCH_ANY))
>  		rep->nonany_branch_mode = true;
>  
> +#ifndef HAVE_LIBUNWIND_SUPPORT
> +	if (dwarf_callchain_users) {
> +		ui__warning("Please install libunwind development packages "
> +			    "during the perf build.\n");
> +	}
> +#endif
> +
>  	return 0;
>  }
>  
> -- 
> 2.17.1

-- 

- Arnaldo