CRAS: Log the length of busyloop

Log the length of busyloop in order to check the busyloop distribution.

BUG=b:157116480
TEST=Trigger busyloop manually and check the chrome://histograms

Change-Id: I7d69e940bc3b5e331c1fdf59df90020f3a4f4ecc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2209009
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
Tested-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Commit-Queue: Yu-Hsuan Hsu <yuhsuan@chromium.org>

3 files changed, 47 insertions, 0 deletions

diff --git a/cras/src/server/audio_thread.c b/cras/src/server/audio_thread.c
index 5482514b..73e61199 100644
--- a/cras/src/server/audio_thread.c
+++ b/cras/src/server/audio_thread.c
@@ -37,6 +37,13 @@
  */
 #define MAX_CONTINUOUS_ZERO_SLEEP_COUNT 2
 
+/*
+ * If the number of continuous zero sleep is equal to this limit, the value
+ * will be recorded immediately. It can ensure all busyloop will be recorded
+ * even if the busyloop does not stop.
+ */
+#define MAX_CONTINUOUS_ZERO_SLEEP_METRIC_LIMIT 1000
+
 /* Messages that can be sent from the main context to the audio thread. */
 enum AUDIO_THREAD_COMMAND {
 	AUDIO_THREAD_ADD_OPEN_DEV,
@@ -783,7 +790,18 @@ static void check_busyloop(struct timespec *wait_ts)
 			busyloop_count++;
 			cras_audio_thread_event_busyloop();
 		}
+		if (continuous_zero_sleep_count ==
+		    MAX_CONTINUOUS_ZERO_SLEEP_METRIC_LIMIT)
+			cras_server_metrics_busyloop_length(
+				continuous_zero_sleep_count);
+
 	} else {
+		if (continuous_zero_sleep_count >=
+			    MAX_CONTINUOUS_ZERO_SLEEP_COUNT &&
+		    continuous_zero_sleep_count <
+			    MAX_CONTINUOUS_ZERO_SLEEP_METRIC_LIMIT)
+			cras_server_metrics_busyloop_length(
+				continuous_zero_sleep_count);
 		continuous_zero_sleep_count = 0;
 	}
 }
diff --git a/cras/src/server/cras_server_metrics.c b/cras/src/server/cras_server_metrics.c
index 69f1014e..3480d945 100644
--- a/cras/src/server/cras_server_metrics.c
+++ b/cras/src/server/cras_server_metrics.c
@@ -22,6 +22,7 @@
 #define METRICS_NAME_BUFFER_SIZE 100
 
 const char kBusyloop[] = "Cras.Busyloop";
+const char kBusyloopLength[] = "Cras.BusyloopLength";
 const char kDeviceTypeInput[] = "Cras.DeviceTypeInput";
 const char kDeviceTypeOutput[] = "Cras.DeviceTypeOutput";
 const char kHighestDeviceDelayInput[] = "Cras.HighestDeviceDelayInput";
@@ -90,6 +91,7 @@ enum CRAS_SERVER_METRICS_TYPE {
 	BT_WIDEBAND_SUPPORTED,
 	BT_WIDEBAND_SELECTED_CODEC,
 	BUSYLOOP,
+	BUSYLOOP_LENGTH,
 	DEVICE_RUNTIME,
 	HIGHEST_DEVICE_DELAY_INPUT,
 	HIGHEST_DEVICE_DELAY_OUTPUT,
@@ -885,6 +887,26 @@ int cras_server_metrics_busyloop(struct timespec *ts, unsigned count)
 	return 0;
 }
 
+int cras_server_metrics_busyloop_length(unsigned length)
+{
+	struct cras_server_metrics_message msg;
+	union cras_server_metrics_data data;
+	int err;
+
+	data.value = length;
+
+	init_server_metrics_msg(&msg, BUSYLOOP_LENGTH, data);
+
+	err = cras_server_metrics_message_send(
+		(struct cras_main_message *)&msg);
+	if (err < 0) {
+		syslog(LOG_ERR,
+		       "Failed to send metrics message: BUSYLOOP_LENGTH");
+		return err;
+	}
+	return 0;
+}
+
 static void metrics_device_runtime(struct cras_server_metrics_device_data data)
 {
 	char metrics_name[METRICS_NAME_BUFFER_SIZE];
@@ -1111,6 +1133,10 @@ static void handle_metrics_message(struct cras_main_message *msg, void *arg)
 	case BUSYLOOP:
 		metrics_busyloop(metrics_msg->data.timespec_data);
 		break;
+	case BUSYLOOP_LENGTH:
+		cras_metrics_log_histogram(
+			kBusyloopLength, metrics_msg->data.value, 0, 1000, 50);
+		break;
 	default:
 		syslog(LOG_ERR, "Unknown metrics type %u",
 		       metrics_msg->metrics_type);
diff --git a/cras/src/server/cras_server_metrics.h b/cras/src/server/cras_server_metrics.h
index 1ca51c09..26adbb2f 100644
--- a/cras/src/server/cras_server_metrics.h
+++ b/cras/src/server/cras_server_metrics.h
@@ -76,6 +76,9 @@ int cras_server_metrics_stream_destroy(const struct cras_rstream *stream);
 /* Logs the number of busyloops for different time periods. */
 int cras_server_metrics_busyloop(struct timespec *ts, unsigned count);
 
+/* Logs the length of busyloops. */
+int cras_server_metrics_busyloop_length(unsigned length);
+
 /* Initialize metrics logging stuff. */
 int cras_server_metrics_init();