perf diff: Display empty space for non paired samples

Currently in 'Baseline' and 'Period Base' columns zero values are
displayed in case no pair is found for the sample. This might be
confusing, using empty space instead.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349448287-18919-9-git-send-email-jolsa@redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/hist.c

@@ -179,7 +179,10 @@ static int hpp__color_baseline(struct perf_hpp *hpp, struct hist_entry *he)
 {
 	double percent = baseline_percent(he);
 
-	return percent_color_snprintf(hpp->buf, hpp->size, " %6.2f%%", percent);
+	if (he->pair)
+		return percent_color_snprintf(hpp->buf, hpp->size, " %6.2f%%", percent);
+	else
+		return scnprintf(hpp->buf, hpp->size, "        ");
 }
 
 static int hpp__entry_baseline(struct perf_hpp *hpp, struct hist_entry *he)
@@ -187,7 +190,10 @@ static int hpp__entry_baseline(struct perf_hpp *hpp, struct hist_entry *he)
 	double percent = baseline_percent(he);
 	const char *fmt = symbol_conf.field_sep ? "%.2f" : " %6.2f%%";
 
-	return scnprintf(hpp->buf, hpp->size, fmt, percent);
+	if (he->pair || symbol_conf.field_sep)
+		return scnprintf(hpp->buf, hpp->size, fmt, percent);
+	else
+		return scnprintf(hpp->buf, hpp->size, "            ");
 }
 
 static int hpp__header_samples(struct perf_hpp *hpp)