diff --git a/cluster_client.cpp b/cluster_client.cpp
index a460a61f..c88f25dc 100644
--- a/cluster_client.cpp
+++ b/cluster_client.cpp
@@ -46,6 +46,8 @@ cluster_client_t::cluster_client_t(ring_loop_t *ringloop, timerfd_manager_t *tfd
         msgr.stop_client(op->peer_fd);
         delete op;
     };
+    msgr.use_sync_send_recv = config["use_sync_send_recv"].bool_value() ||
+        config["use_sync_send_recv"].uint64_value();
 
     st_cli.tfd = tfd;
     st_cli.on_load_config_hook = [this](json11::Json::object & cfg) { on_load_config_hook(cfg); };
diff --git a/fio_cluster.cpp b/fio_cluster.cpp
index 6c28a6a9..eb106c9a 100644
--- a/fio_cluster.cpp
+++ b/fio_cluster.cpp
@@ -3,17 +3,17 @@
 // Random write:
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=4k -direct=1 -fsync=16 -iodepth=16 -rw=randwrite \
-//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -size=1000M
+//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -inode=1 -size=1000M
 //
 // Linear write:
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=128k -direct=1 -fsync=32 -iodepth=32 -rw=write \
-//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -size=1000M
+//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -inode=1 -size=1000M
 //
 // Random read (run with -iodepth=32 or -iodepth=1):
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=4k -direct=1 -iodepth=32 -rw=randread \
-//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -size=1000M
+//     -etcd=127.0.0.1:2379 [-etcd_prefix=/microceph] -inode=1 -size=1000M
 
 #include <sys/types.h>
 #include <sys/socket.h>
diff --git a/messenger.cpp b/messenger.cpp
index 9c867036..a44aaf7c 100644
--- a/messenger.cpp
+++ b/messenger.cpp
@@ -169,7 +169,10 @@ void osd_messenger_t::handle_peer_epoll(int peer_fd, int epoll_events)
         if (cl.read_ready == 1)
         {
             read_ready_clients.push_back(cl.peer_fd);
-            ringloop->wakeup();
+            if (ringloop)
+                ringloop->wakeup();
+            else
+                read_requests();
         }
     }
 }
diff --git a/messenger.h b/messenger.h
index a5729ca0..4dcf6ecd 100644
--- a/messenger.h
+++ b/messenger.h
@@ -233,6 +233,7 @@ struct osd_messenger_t
     int peer_connect_interval = DEFAULT_PEER_CONNECT_INTERVAL;
     int peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
     int log_level = 0;
+    bool use_sync_send_recv = false;
 
     std::map<osd_num_t, osd_wanted_peer_t> wanted_peers;
     std::map<uint64_t, int> osd_peer_fds;
diff --git a/msgr_receive.cpp b/msgr_receive.cpp
index ac0edcfb..e956622b 100644
--- a/msgr_receive.cpp
+++ b/msgr_receive.cpp
@@ -6,13 +6,6 @@ void osd_messenger_t::read_requests()
     {
         int peer_fd = read_ready_clients[i];
         auto & cl = clients[peer_fd];
-        io_uring_sqe* sqe = ringloop->get_sqe();
-        if (!sqe)
-        {
-            read_ready_clients.erase(read_ready_clients.begin(), read_ready_clients.begin() + i);
-            return;
-        }
-        ring_data_t* data = ((ring_data_t*)sqe->user_data);
         if (cl.read_remaining < receive_buffer_size)
         {
             cl.read_iov.iov_base = cl.in_buf;
@@ -27,8 +20,27 @@ void osd_messenger_t::read_requests()
             cl.read_msg.msg_iov = cl.recv_list.get_iovec();
             cl.read_msg.msg_iovlen = cl.recv_list.get_size();
         }
-        data->callback = [this, peer_fd](ring_data_t *data) { handle_read(data->res, peer_fd); };
-        my_uring_prep_recvmsg(sqe, peer_fd, &cl.read_msg, 0);
+        if (ringloop && !use_sync_send_recv)
+        {
+            io_uring_sqe* sqe = ringloop->get_sqe();
+            if (!sqe)
+            {
+                read_ready_clients.erase(read_ready_clients.begin(), read_ready_clients.begin() + i);
+                return;
+            }
+            ring_data_t* data = ((ring_data_t*)sqe->user_data);
+            data->callback = [this, peer_fd](ring_data_t *data) { handle_read(data->res, peer_fd); };
+            my_uring_prep_recvmsg(sqe, peer_fd, &cl.read_msg, 0);
+        }
+        else
+        {
+            int result = recvmsg(peer_fd, &cl.read_msg, 0);
+            if (result < 0)
+            {
+                result = -errno;
+            }
+            handle_read(result, peer_fd);
+        }
     }
     read_ready_clients.clear();
 }
diff --git a/msgr_send.cpp b/msgr_send.cpp
index 0f9fde6e..200ebe39 100644
--- a/msgr_send.cpp
+++ b/msgr_send.cpp
@@ -42,12 +42,6 @@ void osd_messenger_t::outbox_push(osd_op_t *cur_op)
 bool osd_messenger_t::try_send(osd_client_t & cl)
 {
     int peer_fd = cl.peer_fd;
-    io_uring_sqe* sqe = ringloop->get_sqe();
-    if (!sqe)
-    {
-        return false;
-    }
-    ring_data_t* data = ((ring_data_t*)sqe->user_data);
     if (!cl.write_op)
     {
         // pick next command
@@ -103,8 +97,26 @@ bool osd_messenger_t::try_send(osd_client_t & cl)
     }
     cl.write_msg.msg_iov = cl.send_list.get_iovec();
     cl.write_msg.msg_iovlen = cl.send_list.get_size();
-    data->callback = [this, peer_fd](ring_data_t *data) { handle_send(data->res, peer_fd); };
-    my_uring_prep_sendmsg(sqe, peer_fd, &cl.write_msg, 0);
+    if (ringloop && !use_sync_send_recv)
+    {
+        io_uring_sqe* sqe = ringloop->get_sqe();
+        if (!sqe)
+        {
+            return false;
+        }
+        ring_data_t* data = ((ring_data_t*)sqe->user_data);
+        data->callback = [this, peer_fd](ring_data_t *data) { handle_send(data->res, peer_fd); };
+        my_uring_prep_sendmsg(sqe, peer_fd, &cl.write_msg, 0);
+    }
+    else
+    {
+        int result = sendmsg(peer_fd, &cl.write_msg, MSG_NOSIGNAL);
+        if (result < 0)
+        {
+            result = -errno;
+        }
+        handle_send(result, peer_fd);
+    }
     return true;
 }