[PATCH 7/7] perf, tools, stat: Check for frontend stalled for metrics

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Add an extra check for frontend stalled in the metrics.
This avoids an extra column for the --metric-only case
when the CPU does not support frontend stalled.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 tools/perf/util/stat-shadow.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 5e2d2e3..7f87ed7 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -2,6 +2,7 @@
 #include "evsel.h"
 #include "stat.h"
 #include "color.h"
+#include "pmu.h"
 
 enum {
 	CTX_BIT_USER	= 1 << 0,
@@ -35,6 +36,7 @@ static struct stats runtime_dtlb_cache_stats[NUM_CTX][MAX_NR_CPUS];
 static struct stats runtime_cycles_in_tx_stats[NUM_CTX][MAX_NR_CPUS];
 static struct stats runtime_transaction_stats[NUM_CTX][MAX_NR_CPUS];
 static struct stats runtime_elision_stats[NUM_CTX][MAX_NR_CPUS];
+static bool have_frontend_stalled;
 
 struct stats walltime_nsecs_stats;
 
@@ -75,6 +77,7 @@ void perf_stat__reset_shadow_stats(void)
 		sizeof(runtime_transaction_stats));
 	memset(runtime_elision_stats, 0, sizeof(runtime_elision_stats));
 	memset(&walltime_nsecs_stats, 0, sizeof(walltime_nsecs_stats));
+	have_frontend_stalled = pmu_have_event("cpu", "stalled-cycles-frontend");
 }
 
 /*
@@ -323,7 +326,7 @@ void perf_stat__print_shadow_stats(struct perf_evsel *evsel,
 			print_metric(ctxp, NULL, "%7.2f ",
 					"stalled cycles per insn",
 					ratio);
-		} else {
+		} else if (have_frontend_stalled) {
 			print_metric(ctxp, NULL, NULL,
 				     "stalled cycles per insn", 0);
 		}
-- 
2.5.0