perf report: Drop cycles 0 for LBR print

For some platforms, for example Broadwell, it doesn't support cycles
for LBR. But the perf always prints cycles:0, it's not necessary.

The patch refactors the LBR info print code and drops the cycles:0.

For example: perf report --branch-history --no-children --stdio

On Broadwell:
--0.91%--__random_r random_r.c:394 (iterations:2)
          __random_r random_r.c:360 (predicted:0.0%)
          __random_r random_r.c:380 (predicted:0.0%)
          __random_r random_r.c:357

On Skylake:
--1.07%--main div.c:39 (predicted:52.4% cycles:1 iterations:17)
          main div.c:44 (predicted:52.4% cycles:1)
          main div.c:42 (cycles:2)
          compute_flag div.c:28 (cycles:2)
          compute_flag div.c:27 (cycles:1)
          rand rand.c:28 (cycles:1)
          rand rand.c:28 (cycles:1)
          __random random.c:298 (cycles:1)
          __random random.c:297 (cycles:1)
          __random random.c:295 (cycles:1)
          __random random.c:295 (cycles:1)
          __random random.c:295 (cycles:1)
Signed-off-by: Yao Jin <yao.jin@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/1489046786-10061-1-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/callchain.c

@@ -1105,7 +1105,7 @@ int callchain_branch_counts(struct callchain_root *root,
 						  cycles_count);
 }
 
-static int callchain_counts_printf(FILE *fp, char *bf, int bfsize,
+static int counts_str_build(char *bf, int bfsize,
 			     u64 branch_count, u64 predicted_count,
 			     u64 abort_count, u64 cycles_count,
 			     u64 iter_count, u64 samples_count)
@@ -1113,55 +1113,92 @@ static int callchain_counts_printf(FILE *fp, char *bf, int bfsize,
 	double predicted_percent = 0.0;
 	const char *null_str = "";
 	char iter_str[32];
-	char *str;
-	u64 cycles = 0;
-
-	if (branch_count == 0) {
-		if (fp)
-			return fprintf(fp, " (calltrace)");
+	char cycle_str[32];
+	char *istr, *cstr;
+	u64 cycles;
 
+	if (branch_count == 0)
 		return scnprintf(bf, bfsize, " (calltrace)");
-	}
+
+	cycles = cycles_count / branch_count;
 
 	if (iter_count && samples_count) {
+		if (cycles > 0)
+			scnprintf(iter_str, sizeof(iter_str),
+				 " iterations:%" PRId64 "",
+				 iter_count / samples_count);
+		else
 			scnprintf(iter_str, sizeof(iter_str),
-			 ", iterations:%" PRId64 "",
+				 "iterations:%" PRId64 "",
 				 iter_count / samples_count);
-		str = iter_str;
+		istr = iter_str;
 	} else
-		str = (char *)null_str;
+		istr = (char *)null_str;
 
-	predicted_percent = predicted_count * 100.0 / branch_count;
-	cycles = cycles_count / branch_count;
+	if (cycles > 0) {
+		scnprintf(cycle_str, sizeof(cycle_str),
+			  "cycles:%" PRId64 "", cycles);
+		cstr = cycle_str;
+	} else
+		cstr = (char *)null_str;
 
-	if ((predicted_percent >= 100.0) && (abort_count == 0)) {
-		if (fp)
-			return fprintf(fp, " (cycles:%" PRId64 "%s)",
-				       cycles, str);
+	predicted_percent = predicted_count * 100.0 / branch_count;
 
-		return scnprintf(bf, bfsize, " (cycles:%" PRId64 "%s)",
-				 cycles, str);
+	if ((predicted_count == branch_count) && (abort_count == 0)) {
+		if ((cycles > 0) || (istr != (char *)null_str))
+			return scnprintf(bf, bfsize, " (%s%s)", cstr, istr);
+		else
+			return scnprintf(bf, bfsize, "%s", (char *)null_str);
 	}
 
-	if ((predicted_percent < 100.0) && (abort_count == 0)) {
-		if (fp)
-			return fprintf(fp,
-				" (predicted:%.1f%%, cycles:%" PRId64 "%s)",
-				predicted_percent, cycles, str);
+	if ((predicted_count < branch_count) && (abort_count == 0)) {
+		if ((cycles > 0) || (istr != (char *)null_str))
+			return scnprintf(bf, bfsize,
+				" (predicted:%.1f%% %s%s)",
+				predicted_percent, cstr, istr);
+		else {
+			return scnprintf(bf, bfsize,
+				" (predicted:%.1f%%)",
+				predicted_percent);
+		}
+	}
 
+	if ((predicted_count == branch_count) && (abort_count > 0)) {
+		if ((cycles > 0) || (istr != (char *)null_str))
 			return scnprintf(bf, bfsize,
-			" (predicted:%.1f%%, cycles:%" PRId64 "%s)",
-			predicted_percent, cycles, str);
+				" (abort:%" PRId64 " %s%s)",
+				abort_count, cstr, istr);
+		else
+			return scnprintf(bf, bfsize,
+				" (abort:%" PRId64 ")",
+				abort_count);
 	}
 
-	if (fp)
-		return fprintf(fp,
-		" (predicted:%.1f%%, abort:%" PRId64 ", cycles:%" PRId64 "%s)",
-			predicted_percent, abort_count, cycles, str);
+	if ((cycles > 0) || (istr != (char *)null_str))
+		return scnprintf(bf, bfsize,
+			" (predicted:%.1f%% abort:%" PRId64 " %s%s)",
+			predicted_percent, abort_count, cstr, istr);
 
 	return scnprintf(bf, bfsize,
-		" (predicted:%.1f%%, abort:%" PRId64 ", cycles:%" PRId64 "%s)",
-		predicted_percent, abort_count, cycles, str);
+			" (predicted:%.1f%% abort:%" PRId64 ")",
+			predicted_percent, abort_count);
+}
+
+static int callchain_counts_printf(FILE *fp, char *bf, int bfsize,
+				   u64 branch_count, u64 predicted_count,
+				   u64 abort_count, u64 cycles_count,
+				   u64 iter_count, u64 samples_count)
+{
+	char str[128];
+
+	counts_str_build(str, sizeof(str), branch_count,
+			 predicted_count, abort_count, cycles_count,
+			 iter_count, samples_count);
+
+	if (fp)
+		return fprintf(fp, "%s", str);
+
+	return scnprintf(bf, bfsize, "%s", str);
 }
 
 int callchain_list_counts__printf_value(struct callchain_node *node,