diff --git a/include/spdk/histogram_data.h b/include/spdk/histogram_data.h
index 25649397a..5f114fe69 100644
--- a/include/spdk/histogram_data.h
+++ b/include/spdk/histogram_data.h
@@ -106,6 +106,12 @@ __spdk_histogram_get_count(const struct spdk_histogram_data *h, uint32_t range,
 	return h->bucket[(range << SPDK_HISTOGRAM_BUCKET_SHIFT(h)) + index];
 }
 
+static inline uint64_t *
+__spdk_histogram_get_bucket(const struct spdk_histogram_data *h, uint32_t range, uint32_t index)
+{
+	return &h->bucket[(range << SPDK_HISTOGRAM_BUCKET_SHIFT(h)) + index];
+}
+
 static inline void
 spdk_histogram_data_reset(struct spdk_histogram_data *histogram)
 {
@@ -203,6 +209,17 @@ spdk_histogram_data_iterate(const struct spdk_histogram_data *histogram,
 	}
 }
 
+static inline void
+spdk_histogram_data_merge(const struct spdk_histogram_data *dst,
+			  const struct spdk_histogram_data *src)
+{
+	uint64_t i;
+
+	for (i = 0; i < SPDK_HISTOGRAM_NUM_BUCKETS(dst); i++) {
+		dst->bucket[i] += src->bucket[i];
+	}
+}
+
 static inline struct spdk_histogram_data *
 spdk_histogram_data_alloc_sized(uint32_t bucket_shift)
 {