diff --git a/trunk/src/app/srs_app_listener.hpp b/trunk/src/app/srs_app_listener.hpp
index d096e5910..cc20cc756 100644
--- a/trunk/src/app/srs_app_listener.hpp
+++ b/trunk/src/app/srs_app_listener.hpp
@@ -143,6 +143,9 @@ public:
     virtual srs_error_t sendmmsg(mmsghdr* hdr) = 0;
     // Whether sender exceed the max queue, that is, overflow.
     virtual bool overflow() = 0;
+    // Set the queue extra ratio, for example, when mw_msgs > 0, we need larger queue.
+    // For r, 100 means x1, 200 means x2.
+    virtual void set_extra_ratio(int r) = 0;
 };
 
 class SrsUdpMuxSocket
diff --git a/trunk/src/app/srs_app_rtc_conn.cpp b/trunk/src/app/srs_app_rtc_conn.cpp
index 890540c1c..9414741ab 100644
--- a/trunk/src/app/srs_app_rtc_conn.cpp
+++ b/trunk/src/app/srs_app_rtc_conn.cpp
@@ -674,26 +674,32 @@ srs_error_t SrsRtcSenderThread::cycle()
     srs_error_t err = srs_success;
 
     SrsSource* source = NULL;
+    SrsRequest* req = &rtc_session->request;
 
     // TODO: FIXME: Should refactor it, directly use http server as handler.
     ISrsSourceHandler* handler = _srs_hybrid->srs()->instance();
-    if ((err = _srs_sources->fetch_or_create(&rtc_session->request, handler, &source)) != srs_success) {
+    if ((err = _srs_sources->fetch_or_create(req, handler, &source)) != srs_success) {
         return srs_error_wrap(err, "rtc fetch source failed");
     }
 
     SrsConsumer* consumer = NULL;
     SrsAutoFree(SrsConsumer, consumer);
     if ((err = source->create_consumer(NULL, consumer)) != srs_success) {
-        return srs_error_wrap(err, "rtc create consumer, source url=%s", rtc_session->request.get_stream_url().c_str());
+        return srs_error_wrap(err, "rtc create consumer, source url=%s", req->get_stream_url().c_str());
     }
 
-    // TODO: FIXME: Support reload.
-    SrsRequest* req = &rtc_session->request;
     realtime = _srs_config->get_realtime_enabled(req->vhost, true);
     mw_sleep = _srs_config->get_mw_sleep(req->vhost, true);
     mw_msgs = _srs_config->get_mw_msgs(req->vhost, realtime, true);
 
-    srs_trace("RTC source url=%s, source_id=[%d][%d], encrypt=%d, realtime=%d, mw_sleep=%dms, mw_msgs=%d", rtc_session->request.get_stream_url().c_str(),
+    // We merged write more messages, so we need larger queue.
+    if (mw_msgs > 2) {
+        sender->set_extra_ratio(150);
+    } else if (mw_msgs > 0) {
+        sender->set_extra_ratio(80);
+    }
+
+    srs_trace("RTC source url=%s, source_id=[%d][%d], encrypt=%d, realtime=%d, mw_sleep=%dms, mw_msgs=%d", req->get_stream_url().c_str(),
         ::getpid(), source->source_id(), rtc_session->encrypt, realtime, srsu2msi(mw_sleep), mw_msgs);
 
     SrsRtcPackets pkts;
@@ -1846,6 +1852,10 @@ SrsUdpMuxSender::SrsUdpMuxSender(SrsRtcServer* s)
     cache_pos = 0;
     max_sendmmsg = 0;
     queue_length = 0;
+    extra_ratio = 0;
+    extra_queue = 0;
+    gso = false;
+    nn_senders = 0;
 
     _srs_config->subscribe(this);
 }
@@ -1877,16 +1887,17 @@ srs_error_t SrsUdpMuxSender::initialize(srs_netfd_t fd, int senders)
     }
 
     max_sendmmsg = _srs_config->get_rtc_server_sendmmsg();
-    bool gso = _srs_config->get_rtc_server_gso();
+    gso = _srs_config->get_rtc_server_gso();
     queue_length = srs_max(128, _srs_config->get_rtc_server_queue_length());
+    nn_senders = senders;
 
     // For no GSO, we need larger queue.
     if (!gso) {
         queue_length *= 2;
     }
 
-    srs_trace("UDP sender #%d init ok, max_sendmmsg=%d, gso=%d, queue_max=%dx%d", srs_netfd_fileno(fd),
-        max_sendmmsg, gso, queue_length, senders);
+    srs_trace("RTC sender #%d init ok, max_sendmmsg=%d, gso=%d, queue_max=%dx%d, extra_ratio=%d/%d", srs_netfd_fileno(fd),
+        max_sendmmsg, gso, queue_length, nn_senders, extra_ratio, extra_queue);
 
     return err;
 }
@@ -1944,7 +1955,21 @@ srs_error_t SrsUdpMuxSender::fetch(mmsghdr** pphdr)
 
 bool SrsUdpMuxSender::overflow()
 {
-    return cache_pos > queue_length;
+    return cache_pos > queue_length + extra_queue;
+}
+
+void SrsUdpMuxSender::set_extra_ratio(int r)
+{
+    // We use the larger extra ratio, because all vhosts shares the senders.
+    if (extra_ratio > r) {
+        return;
+    }
+
+    extra_ratio = r;
+    extra_queue = queue_length * r / 100;
+
+    srs_trace("RTC sender #%d extra queue, max_sendmmsg=%d, gso=%d, queue_max=%dx%d, extra_ratio=%d/%d, cache=%d/%d/%d", srs_netfd_fileno(lfd),
+        max_sendmmsg, gso, queue_length, nn_senders, extra_ratio, extra_queue, cache_pos, (int)cache.size(), (int)hotspot.size());
 }
 
 srs_error_t SrsUdpMuxSender::sendmmsg(mmsghdr* hdr)
diff --git a/trunk/src/app/srs_app_rtc_conn.hpp b/trunk/src/app/srs_app_rtc_conn.hpp
index 4cf19d727..3ad6a1072 100644
--- a/trunk/src/app/srs_app_rtc_conn.hpp
+++ b/trunk/src/app/srs_app_rtc_conn.hpp
@@ -307,6 +307,9 @@ private:
 private:
     srs_cond_t cond;
     bool waiting_msgs;
+    bool gso;
+    int nn_senders;
+private:
     // Hotspot msgs, we are working on it.
     // @remark We will wait util all messages are ready.
     std::vector<mmsghdr> hotspot;
@@ -317,6 +320,9 @@ private:
     int max_sendmmsg;
     // The total queue length, for each sender.
     int queue_length;
+    // The extra queue ratio.
+    int extra_ratio;
+    int extra_queue;
 public:
     SrsUdpMuxSender(SrsRtcServer* s);
     virtual ~SrsUdpMuxSender();
@@ -328,6 +334,8 @@ public:
     virtual srs_error_t fetch(mmsghdr** pphdr);
     virtual srs_error_t sendmmsg(mmsghdr* hdr);
     virtual bool overflow();
+    virtual void set_extra_ratio(int r);
+public:
     virtual srs_error_t cycle();
 // interface ISrsReloadHandler
 public: