Re: [PATCH v1 3/8] perf stat: Display "none" for NaN with metric only json

[Namhyung Kim <namhyung@kernel.org>]

On Fri, Oct 04, 2024 at 04:41:15PM -0700, Ian Rogers wrote:
> Return earlier for an empty unit case. If snprintf of the fmt doesn't
> produce digits between vals and ends, as happens with NaN, make the
> value "none" as happens in print_metric_end.

Then it could be "NaN" or is there any other case?  But probably "none"
would be more generic.

Thanks,
Namhyung

> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/stat-display.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 5402998881c4..e392ee5efb45 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -609,19 +609,22 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
>  {
>  	struct outstate *os = ctx;
>  	FILE *out = os->fh;
> -	char buf[64], *vals, *ends;
> +	char buf[64], *ends;
>  	char tbuf[1024];
> +	const char *vals;
>  
>  	if (!valid_only_metric(unit))
>  		return;
>  	unit = fixunit(tbuf, os->evsel, unit);
> +	if (!unit[0])
> +		return;
>  	snprintf(buf, sizeof(buf), fmt ?: "", val);
> -	ends = vals = skip_spaces(buf);
> +	vals = ends = skip_spaces(buf);
>  	while (isdigit(*ends) || *ends == '.')
>  		ends++;
>  	*ends = 0;
> -	if (!unit[0] || !vals[0])
> -		return;
> +	if (!vals[0])
> +		vals = "none";
>  	fprintf(out, "%s\"%s\" : \"%s\"", os->first ? "" : ", ", unit, vals);
>  	os->first = false;
>  }
> -- 
> 2.47.0.rc0.187.ge670bccf7e-goog
>