diff --git a/artiq/runtime/ksupport.c b/artiq/runtime/ksupport.c
index 3fcedfba3..780818dc2 100644
--- a/artiq/runtime/ksupport.c
+++ b/artiq/runtime/ksupport.c
@@ -475,7 +475,6 @@ void send_rpc(int service, const char *tag, ...)
 {
     struct msg_rpc_send request;
 
-    request.now = now;
     if(service != 0)
         request.type = MESSAGE_TYPE_RPC_SEND;
     else
diff --git a/artiq/runtime/messages.h b/artiq/runtime/messages.h
index a3aa0a819..1a297d630 100644
--- a/artiq/runtime/messages.h
+++ b/artiq/runtime/messages.h
@@ -87,7 +87,6 @@ struct msg_watchdog_clear {
 
 struct msg_rpc_send {
     int type;
-    long long int now;
     int service;
     const char *tag;
     va_list args;
diff --git a/artiq/runtime/session.c b/artiq/runtime/session.c
index 201c79dee..517614e90 100644
--- a/artiq/runtime/session.c
+++ b/artiq/runtime/session.c
@@ -983,12 +983,6 @@ static int process_kmsg(struct msg_base *umsg)
         case MESSAGE_TYPE_RPC_BATCH: {
             struct msg_rpc_send *msg = (struct msg_rpc_send *)umsg;
 
-            /*
-             * save now in case the RPC stops the kernel
-             * (e.g. pause with preemption)
-             */
-            now = msg->now;
-
             if(!send_rpc_request(msg->service, msg->tag, msg->args)) {
                 core_log("Failed to send RPC request (service %d, tag %s)\n",
                          msg->service, msg->tag);