diff --git a/observation/src/biotop/biotop.h b/observation/src/biotop/biotop.h
new file mode 100644
index 0000000000000000000000000000000000000000..3684f75b79afc2d49d176430e8df79cec2c87e0c
--- /dev/null
+++ b/observation/src/biotop/biotop.h
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+#ifndef __BIOTOP_H
+#define __BIOTOP_H
+
+#define REQ_OP_BIT	8
+#define REQ_OP_MASK	((1 << REQ_OP_BIT) - 1)
+
+#define TASK_COMM_LEN	16
+
+/* For saving the timestamp and __data_len of each request */
+struct start_req_t {
+	__u64	ts;
+	__u64	data_len;
+};
+
+/* For saving process info by request */
+struct who_t {
+	pid_t	pid;
+	char	name[TASK_COMM_LEN];
+};
+
+#endif