diff --git a/client/metrics.go b/client/metrics.go
index e0b29fb8bcc..f3c47d7e787 100644
--- a/client/metrics.go
+++ b/client/metrics.go
@@ -105,7 +105,7 @@ func initMetrics(constLabels prometheus.Labels) {
 			Subsystem:   "request",
 			Name:        "tso_batch_send_latency",
 			ConstLabels: constLabels,
-			Buckets:     prometheus.ExponentialBuckets(1, 2, 34), // 1ns ~ 8s
+			Buckets:     prometheus.ExponentialBuckets(0.0005, 2, 13),
 			Help:        "tso batch send latency",
 		})
 
diff --git a/client/tso_stream.go b/client/tso_stream.go
index 14b72bc697b..dd5b9422aae 100644
--- a/client/tso_stream.go
+++ b/client/tso_stream.go
@@ -139,7 +139,7 @@ func (s *pdTSOStream) processRequests(
 		}
 		return
 	}
-	tsoBatchSendLatency.Observe(float64(time.Since(batchStartTime)))
+	tsoBatchSendLatency.Observe(time.Since(batchStartTime).Seconds())
 	resp, err := s.stream.Recv()
 	if err != nil {
 		if err == io.EOF {
@@ -195,7 +195,7 @@ func (s *tsoTSOStream) processRequests(
 		}
 		return
 	}
-	tsoBatchSendLatency.Observe(float64(time.Since(batchStartTime)))
+	tsoBatchSendLatency.Observe(time.Since(batchStartTime).Seconds())
 	resp, err := s.stream.Recv()
 	if err != nil {
 		if err == io.EOF {
diff --git a/server/metrics.go b/server/metrics.go
index 0935008a420..fdcc5b4be22 100644
--- a/server/metrics.go
+++ b/server/metrics.go
@@ -45,7 +45,7 @@ var (
 			Subsystem: "scheduler",
 			Name:      "region_heartbeat_latency_seconds",
 			Help:      "Bucketed histogram of latency (s) of receiving heartbeat.",
-			Buckets:   prometheus.ExponentialBuckets(1, 2, 12),
+			Buckets:   prometheus.ExponentialBuckets(0.0005, 2, 13),
 		}, []string{"address", "store"})
 
 	metadataGauge = prometheus.NewGaugeVec(