linux-kernel - Re: [PATCH v1 06/10] perf, tools, report: Print better message for JITed code

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Message-ID: <20190311203302.GB10690@kernel.org>
Date:   Mon, 11 Mar 2019 17:33:02 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Andi Kleen <andi@...stfloor.org>
Cc:     jolsa@...nel.org, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH v1 06/10] perf, tools, report: Print better message for
 JITed code

Em Mon, Mar 11, 2019 at 01:24:42PM -0700, Andi Kleen escreveu:
> From: Andi Kleen <ak@...ux.intel.com>
> 
> The message about missing /tmp/perf-* for JITed code is quite confusing
> to users. Add a better error message, but only print it once.
> 
> Signed-off-by: Andi Kleen <ak@...ux.intel.com>
> ---
>  tools/perf/util/map.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index fbeb0c6efaa6..d476b76abc6a 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -316,6 +316,15 @@ int map__load(struct map *map)
>  
>  	nr = dso__load(map->dso, map);
>  	if (nr < 0) {
> +		if (!strncmp(map->dso->name, "/tmp/perf-", 10)) {
> +			static bool warned;
> +			if (!warned) {
> +				pr_err("Cannot find executable, JITed code present? May need agent.\n");
> +				warned = true;
> +			}

Please use WARN_ON_ONCE(), we have it in tools/include/asm/bug.h, just
like the kernel.

> +			return -1;
> +		}
> +
>  		if (map->dso->has_build_id) {
>  			char sbuild_id[SBUILD_ID_SIZE];
>  
> -- 
> 2.20.1

-- 

- Arnaldo