change the start_t time to be receiving the first request time not the system boot time

runtime/src/listener_thread.c

@@ -14,6 +14,8 @@
 #include "http_session_perf_log.h"
 
 extern thread_local int thread_id;
+extern bool first_request_comming;
+time_t t_start;
 static void listener_thread_unregister_http_session(struct http_session *http);
 static void panic_on_epoll_error(struct epoll_event *evt);
 
@@ -192,6 +194,11 @@ on_client_request_arrival(int client_socket, const struct sockaddr *client_addre
 static void
 on_client_request_receiving(struct http_session *session)
 {
+	if (first_request_comming == false){
+        	t_start = time(NULL);
+                first_request_comming = true;
+        }
+
 	/* Read HTTP request */
 	int rc = http_session_receive_request(session, (void_star_cb)listener_thread_register_http_session);
 	if (likely(rc == 0)) {

runtime/src/main.c

@@ -41,9 +41,9 @@ enum RUNTIME_SIGALRM_HANDLER runtime_sigalrm_handler = RUNTIME_SIGALRM_HANDLER_B
 bool     runtime_preemption_enabled = true;
 uint32_t runtime_quantum_us         = 5000; /* 5ms */
 uint64_t runtime_boot_timestamp;
-time_t t_start;
 pid_t    runtime_pid = 0;
 thread_local int thread_id = -1;
+bool first_request_comming = false;
 
 /**
  * Returns instructions on use of CLI if used incorrectly
@@ -496,7 +496,6 @@ main(int argc, char **argv)
 	}
 
 	runtime_boot_timestamp = __getcycles();
-	t_start = time(NULL);
 
 	for (int tenant_idx = 0; tenant_idx < tenant_config_vec_len; tenant_idx++) {
 		tenant_config_deinit(&tenant_config_vec[tenant_idx]);