From 10297fab519811845b549a8af40a6bcbd23411e8 Mon Sep 17 00:00:00 2001
From: winlin <winlin@vip.126.com>
Date: Fri, 12 Dec 2014 21:51:06 +0800
Subject: [PATCH] fix #257, support 0.1s+ latency. 2.0.70

---
 README.md                               |  2 +
 trunk/conf/full.conf                    | 13 ++++++
 trunk/conf/realtime.conf                |  3 +-
 trunk/research/players/js/srs.player.js |  2 +-
 trunk/research/players/srs_player.html  | 14 ++++++-
 trunk/src/app/srs_app_config.cpp        | 32 +++++++++++++--
 trunk/src/app/srs_app_config.hpp        |  6 +++
 trunk/src/app/srs_app_recv_thread.cpp   | 32 +++++++++++++--
 trunk/src/app/srs_app_recv_thread.hpp   |  4 ++
 trunk/src/app/srs_app_reload.cpp        |  5 +++
 trunk/src/app/srs_app_reload.hpp        |  1 +
 trunk/src/app/srs_app_rtmp_conn.cpp     | 54 ++++++++++++++++++++-----
 trunk/src/app/srs_app_rtmp_conn.hpp     |  4 ++
 trunk/src/app/srs_app_source.cpp        | 13 ++++--
 trunk/src/app/srs_app_source.hpp        |  3 +-
 trunk/src/core/srs_core.hpp             |  2 +-
 trunk/src/core/srs_core_performance.hpp |  9 +++++
 trunk/src/kernel/srs_kernel_utility.cpp |  8 ++--
 trunk/src/kernel/srs_kernel_utility.hpp |  2 +-
 19 files changed, 179 insertions(+), 30 deletions(-)
 mode change 100644 => 100755 trunk/research/players/srs_player.html

diff --git a/README.md b/README.md
index c21401c974..96890e4d61 100755
--- a/README.md
+++ b/README.md
@@ -453,6 +453,7 @@ Supported operating systems and hardware:
 [CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_SrsLibrtmp#publish-audio-raw-stream),
 [EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_SrsLibrtmp#publish-audio-raw-stream)
 ) by srs-librtmp.
+1. Support 0.1s+ latency, read [#257](https://github.com/winlinvip/simple-rtmp-server/issues/257).
 1. [no-plan] Support <500ms latency, FRSC(Fast RTMP-compatible Stream Channel tech).
 1. [no-plan] Support RTMP 302 redirect [#92](https://github.com/winlinvip/simple-rtmp-server/issues/92).
 1. [no-plan] Support multiple processes, for both origin and edge
@@ -486,6 +487,7 @@ Supported operating systems and hardware:
 * 2013-10-17, Created.<br/>
 
 ## History
+* v2.0, 2014-12-12, fix [#257](https://github.com/winlinvip/simple-rtmp-server/issues/257), support 0.1s+ latency. 2.0.70
 * v2.0, 2014-12-08, update wiki for mr([EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_LowLatency#merged-read), [CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_LowLatency#merged-read)) and mw([EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_LowLatency#merged-write), [CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_LowLatency#merged-write)).
 * v2.0, 2014-12-07, fix [#251](https://github.com/winlinvip/simple-rtmp-server/issues/251), 10k+ clients, use queue cond wait and fast vector. 2.0.67
 * v2.0, 2014-12-05, fix [#251](https://github.com/winlinvip/simple-rtmp-server/issues/251), 9k+ clients, use fast cache for msgs queue. 2.0.57
diff --git a/trunk/conf/full.conf b/trunk/conf/full.conf
index de0ca04987..343e51b8d1 100755
--- a/trunk/conf/full.conf
+++ b/trunk/conf/full.conf
@@ -145,6 +145,13 @@ vhost __defaultVhost__ {
 # the MR(merged-read) setting for publisher.
 # the MW(merged-write) settings for player.
 vhost mrw.srs.com {
+    # whether enable min delay mode for vhost.
+    # for min latence mode:
+    # 1. disable the mr for vhost.
+    # 2. use timeout for cond wait for consumer queue.
+    # @see https://github.com/winlinvip/simple-rtmp-server/issues/257
+    # default: on
+    min_latency     off;
     # about MR, read https://github.com/winlinvip/simple-rtmp-server/issues/241
     mr {
         # whether enable the MR(merged-read)
@@ -440,6 +447,12 @@ vhost debug.srs.com {
 
 # the vhost for min delay, donot cache any stream.
 vhost min.delay.com {
+    # @see vhost mrw.srs.com for detail.
+    min_latency     on;
+    mr {
+        enabled     off;
+    }
+    mw_latency      100;
     # whether cache the last gop.
     # if on, cache the last gop and dispatch to client,
     #   to enabled fast startup for client, client play immediately.
diff --git a/trunk/conf/realtime.conf b/trunk/conf/realtime.conf
index 00ccd03c54..4ac824b6f4 100755
--- a/trunk/conf/realtime.conf
+++ b/trunk/conf/realtime.conf
@@ -1,5 +1,5 @@
 # the config for srs to delivery realtime RTMP stream
-# @see https://github.com/winlinvip/simple-rtmp-server/wiki/v1_CN_SampleRealtime
+# @see https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_SampleRealtime
 # @see full.conf for detail config.
 
 listen              1935;
@@ -7,6 +7,7 @@ max_connections     1000;
 vhost __defaultVhost__ {
     gop_cache       off;
     queue_length    10;
+    min_latency     on;
     mr {
         enabled     off;
     }
diff --git a/trunk/research/players/js/srs.player.js b/trunk/research/players/js/srs.player.js
index dad0ba9278..f04859ca9c 100755
--- a/trunk/research/players/js/srs.player.js
+++ b/trunk/research/players/js/srs.player.js
@@ -22,7 +22,7 @@ function SrsPlayer(container, width, height, private_object) {
     this.height = height;
     this.id = SrsPlayer.__id++;
     this.stream_url = null;
-    this.buffer_time = 0.8; // default to 0.8
+    this.buffer_time = 0.3; // default to 0.3
     this.volume = 1.0; // default to 100%
     this.callbackObj = null;
     
diff --git a/trunk/research/players/srs_player.html b/trunk/research/players/srs_player.html
old mode 100644
new mode 100755
index 4e26ed0468..0345d16f59
--- a/trunk/research/players/srs_player.html
+++ b/trunk/research/players/srs_player.html
@@ -96,7 +96,7 @@
                 
                 srs_player = new SrsPlayer("player_id", srs_get_player_width(), srs_get_player_height());
                 srs_player.on_player_ready = function() {
-                    select_buffer_time("#btn_bt_0_8", 0.8);
+                    select_buffer_time("#btn_bt_0_1", 0.1);
                     this.play(url);
                 };
                 srs_player.on_player_metadata = function(metadata) {
@@ -231,6 +231,15 @@
             }
             
             if (true) {
+                $("#btn_bt_0_1").click(function(){
+                    select_buffer_time("#btn_bt_0_1", 0.1);
+                });
+                $("#btn_bt_0_2").click(function(){
+                    select_buffer_time("#btn_bt_0_2", 0.2);
+                });
+                $("#btn_bt_0_3").click(function(){
+                    select_buffer_time("#btn_bt_0_3", 0.3);
+                });
                 $("#btn_bt_0_5").click(function(){
                     select_buffer_time("#btn_bt_0_5", 0.5);
                 });
@@ -504,6 +513,9 @@ <h3><a href="https://github.com/winlinvip/simple-rtmp-server">SrsPlayer</a></h3>
             <div class="btn-group dropup">
                 <button class="btn dropdown-toggle" data-toggle="dropdown">缓冲区<span class="caret"></span></button>
                 <ul class="dropdown-menu">
+                    <li><a id="btn_bt_0_1" href="#">0.1秒(实时)</a></li>
+                    <li><a id="btn_bt_0_2" href="#">0.2秒(实时)</a></li>
+                    <li><a id="btn_bt_0_3" href="#">0.3秒(实时)</a></li>
                     <li><a id="btn_bt_0_5" href="#">0.5秒(实时)</a></li>
                     <li><a id="btn_bt_0_8" href="#">0.8秒(会议)</a></li>
                     <li><a id="btn_bt_1" href="#">1秒(低延迟)</a></li>
diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index b68b3864e5..57d840dac1 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -852,6 +852,17 @@ int SrsConfig::reload_vhost(SrsConfDirective* old_root)
                 }
                 srs_trace("vhost %s reload mw success.", vhost.c_str());
             }
+            // min_latency, only one per vhost
+            if (!srs_directive_equals(new_vhost->get("min_latency"), old_vhost->get("min_latency"))) {
+                for (it = subscribes.begin(); it != subscribes.end(); ++it) {
+                    ISrsReloadHandler* subscribe = *it;
+                    if ((ret = subscribe->on_reload_vhost_realtime(vhost)) != ERROR_SUCCESS) {
+                        srs_error("vhost %s notify subscribes min_latency failed. ret=%d", vhost.c_str(), ret);
+                        return ret;
+                    }
+                }
+                srs_trace("vhost %s reload min_latency success.", vhost.c_str());
+            }
             // http, only one per vhost.
             if (!srs_directive_equals(new_vhost->get("http"), old_vhost->get("http"))) {
                 for (it = subscribes.begin(); it != subscribes.end(); ++it) {
@@ -1350,7 +1361,7 @@ int SrsConfig::check_config()
                 && n != "time_jitter" 
                 && n != "atc" && n != "atc_auto"
                 && n != "debug_srs_upnode"
-                && n != "mr" && n != "mw_latency"
+                && n != "mr" && n != "mw_latency" && n != "min_latency"
             ) {
                 ret = ERROR_SYSTEM_CONFIG_INVALID;
                 srs_error("unsupported vhost directive %s, ret=%d", n.c_str(), ret);
@@ -2125,7 +2136,6 @@ int SrsConfig::get_chunk_size(string vhost)
 
 bool SrsConfig::get_mr_enabled(string vhost)
 {
-    
     SrsConfDirective* conf = get_vhost(vhost);
 
     if (!conf) {
@@ -2147,7 +2157,6 @@ bool SrsConfig::get_mr_enabled(string vhost)
 
 int SrsConfig::get_mr_sleep_ms(string vhost)
 {
-    
     SrsConfDirective* conf = get_vhost(vhost);
 
     if (!conf) {
@@ -2169,7 +2178,6 @@ int SrsConfig::get_mr_sleep_ms(string vhost)
 
 int SrsConfig::get_mw_sleep_ms(string vhost)
 {
-
     SrsConfDirective* conf = get_vhost(vhost);
 
     if (!conf) {
@@ -2184,6 +2192,22 @@ int SrsConfig::get_mw_sleep_ms(string vhost)
     return ::atoi(conf->arg0().c_str());
 }
 
+bool SrsConfig::get_realtime_enabled(string vhost)
+{
+    SrsConfDirective* conf = get_vhost(vhost);
+
+    if (!conf) {
+        return SRS_PERF_MIN_LATENCY_ENABLED;
+    }
+
+    conf = conf->get("min_latency");
+    if (!conf || conf->arg0() != "off") {
+        return SRS_PERF_MIN_LATENCY_ENABLED;
+    }
+
+    return false;
+}
+
 int SrsConfig::get_global_chunk_size()
 {
     SrsConfDirective* conf = root->get("chunk_size");
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 2c01d02a45..5abc3c126b 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -545,6 +545,12 @@ class SrsConfig
     */
     // TODO: FIXME: add utest for mw config.
     virtual int                 get_mw_sleep_ms(std::string vhost);
+    /**
+    * whether min latency mode enabled.
+    * @param vhost, the vhost to get the min_latency.
+    */
+    // TODO: FIXME: add utest for min_latency.
+    virtual bool                get_realtime_enabled(std::string vhost);
 private:
     /**
     * get the global chunk size.
diff --git a/trunk/src/app/srs_app_recv_thread.cpp b/trunk/src/app/srs_app_recv_thread.cpp
index 10b482f530..310c5ebecf 100644
--- a/trunk/src/app/srs_app_recv_thread.cpp
+++ b/trunk/src/app/srs_app_recv_thread.cpp
@@ -251,6 +251,8 @@ SrsPublishRecvThread::SrsPublishRecvThread(
     mr = _srs_config->get_mr_enabled(req->vhost);
     mr_sleep = _srs_config->get_mr_sleep_ms(req->vhost);
     
+    realtime = _srs_config->get_realtime_enabled(req->vhost);
+    
     _srs_config->subscribe(this);
 }
 
@@ -340,6 +342,10 @@ int SrsPublishRecvThread::handle(SrsCommonMessage* msg)
     int ret = ERROR_SUCCESS;
 
     _nb_msgs++;
+    
+    // log to show the time of recv thread.
+    srs_verbose("recv thread now=%"PRId64"us, got msg time=%"PRId64"ms, size=%d",
+        srs_update_system_time_ms(), msg->header.timestamp, msg->size);
 
     // the rtmp connection will handle this message
     ret = _conn->handle_publish_message(_source, msg, _is_fmle, _is_edge);
@@ -363,7 +369,7 @@ void SrsPublishRecvThread::on_recv_error(int ret)
 #ifdef SRS_PERF_MERGED_READ
 void SrsPublishRecvThread::on_read(ssize_t nread)
 {
-    if (!mr) {
+    if (!mr || realtime) {
         return;
     }
     
@@ -386,6 +392,10 @@ void SrsPublishRecvThread::on_read(ssize_t nread)
 int SrsPublishRecvThread::on_reload_vhost_mr(string vhost)
 {
     int ret = ERROR_SUCCESS;
+    
+    if (req->vhost != vhost) {
+        return ret;
+    }
 
     // the mr settings, 
     // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
@@ -419,6 +429,21 @@ int SrsPublishRecvThread::on_reload_vhost_mr(string vhost)
     return ret;
 }
 
+int SrsPublishRecvThread::on_reload_vhost_realtime(string vhost)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (req->vhost != vhost) {
+        return ret;
+    }
+    
+    bool realtime_enabled = _srs_config->get_realtime_enabled(req->vhost);
+    srs_trace("realtime changed %d=>%d", realtime, realtime_enabled);
+    realtime = realtime_enabled;
+    
+    return ret;
+}
+
 void SrsPublishRecvThread::set_socket_buffer(int sleep_ms)
 {
     // the bytes:
@@ -446,8 +471,9 @@ void SrsPublishRecvThread::set_socket_buffer(int sleep_ms)
     }
     getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &nb_rbuf, &sock_buf_size);
 
-    srs_trace("mr change sleep %d=>%d, erbuf=%d, rbuf %d=>%d, sbytes=%d",
-        mr_sleep, sleep_ms, socket_buffer_size, onb_rbuf, nb_rbuf, SRS_MR_SMALL_BYTES);
+    srs_trace("mr change sleep %d=>%d, erbuf=%d, rbuf %d=>%d, sbytes=%d, realtime=%d",
+        mr_sleep, sleep_ms, socket_buffer_size, onb_rbuf, nb_rbuf, 
+        SRS_MR_SMALL_BYTES, realtime);
 
     rtmp->set_recv_buffer(nb_rbuf);
 }
diff --git a/trunk/src/app/srs_app_recv_thread.hpp b/trunk/src/app/srs_app_recv_thread.hpp
index 957c8d85b4..e97639d1d4 100644
--- a/trunk/src/app/srs_app_recv_thread.hpp
+++ b/trunk/src/app/srs_app_recv_thread.hpp
@@ -153,6 +153,9 @@ class SrsPublishRecvThread : virtual public ISrsMessageHandler
     bool mr;
     int mr_fd;
     int mr_sleep;
+    // for realtime
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/257
+    bool realtime;
     // the recv thread error code.
     int recv_error_code;
     SrsRtmpConn* _conn;
@@ -193,6 +196,7 @@ class SrsPublishRecvThread : virtual public ISrsMessageHandler
 // interface ISrsReloadHandler
 public:
     virtual int on_reload_vhost_mr(std::string vhost);
+    virtual int on_reload_vhost_realtime(std::string vhost);
 private:
     virtual void set_socket_buffer(int sleep_ms);
 };
diff --git a/trunk/src/app/srs_app_reload.cpp b/trunk/src/app/srs_app_reload.cpp
index b1f81f5ecd..c632797d00 100644
--- a/trunk/src/app/srs_app_reload.cpp
+++ b/trunk/src/app/srs_app_reload.cpp
@@ -150,6 +150,11 @@ int ISrsReloadHandler::on_reload_vhost_mw(string /*vhost*/)
     return ERROR_SUCCESS;
 }
 
+int ISrsReloadHandler::on_reload_vhost_realtime(string /*vhost*/)
+{
+    return ERROR_SUCCESS;
+}
+
 int ISrsReloadHandler::on_reload_vhost_chunk_size(string /*vhost*/)
 {
     return ERROR_SUCCESS;
diff --git a/trunk/src/app/srs_app_reload.hpp b/trunk/src/app/srs_app_reload.hpp
index b9377bff57..d69d441a73 100644
--- a/trunk/src/app/srs_app_reload.hpp
+++ b/trunk/src/app/srs_app_reload.hpp
@@ -67,6 +67,7 @@ class ISrsReloadHandler
     virtual int on_reload_vhost_dvr(std::string vhost);
     virtual int on_reload_vhost_mr(std::string vhost);
     virtual int on_reload_vhost_mw(std::string vhost);
+    virtual int on_reload_vhost_realtime(std::string vhost);
     virtual int on_reload_vhost_chunk_size(std::string vhost);
     virtual int on_reload_vhost_transcode(std::string vhost);
     virtual int on_reload_ingest_removed(std::string vhost, std::string ingest_id);
diff --git a/trunk/src/app/srs_app_rtmp_conn.cpp b/trunk/src/app/srs_app_rtmp_conn.cpp
index e866f55e1b..a86cfaf8cf 100644
--- a/trunk/src/app/srs_app_rtmp_conn.cpp
+++ b/trunk/src/app/srs_app_rtmp_conn.cpp
@@ -50,6 +50,7 @@ using namespace std;
 #include <srs_protocol_amf0.hpp>
 #include <srs_app_recv_thread.hpp>
 #include <srs_core_performance.hpp>
+#include <srs_kernel_utility.hpp>
 
 // when stream is busy, for example, streaming is already
 // publishing, when a new client to request to publish,
@@ -86,6 +87,7 @@ SrsRtmpConn::SrsRtmpConn(SrsServer* srs_server, st_netfd_t client_stfd)
     
     mw_sleep = SRS_PERF_MW_SLEEP;
     mw_enabled = false;
+    realtime = SRS_PERF_MIN_LATENCY_ENABLED;
     
     _srs_config->subscribe(this);
 }
@@ -212,14 +214,35 @@ int SrsRtmpConn::on_reload_vhost_removed(string vhost)
     return ret;
 }
 
-int SrsRtmpConn::on_reload_vhost_mw(string /*vhost*/)
+int SrsRtmpConn::on_reload_vhost_mw(string vhost)
 {
+    int ret = ERROR_SUCCESS;
+    
+    if (req->vhost != vhost) {
+        return ret;
+    }
+    
     int sleep_ms = _srs_config->get_mw_sleep_ms(req->vhost);
     
     // when mw_sleep changed, resize the socket send buffer.
     change_mw_sleep(sleep_ms);
 
-    return ERROR_SUCCESS;
+    return ret;
+}
+
+int SrsRtmpConn::on_reload_vhost_realtime(string vhost)
+{
+    int ret = ERROR_SUCCESS;
+    
+    if (req->vhost != vhost) {
+        return ret;
+    }
+    
+    bool realtime_enabled = _srs_config->get_realtime_enabled(req->vhost);
+    srs_trace("realtime changed %d=>%d", realtime, realtime_enabled);
+    realtime = realtime_enabled;
+
+    return ret;
 }
 
 int64_t SrsRtmpConn::get_send_bytes_delta()
@@ -570,6 +593,7 @@ int SrsRtmpConn::do_playing(SrsSource* source, SrsQueueRecvThread* trd)
     // when mw_sleep changed, resize the socket send buffer.
     mw_enabled = true;
     change_mw_sleep(_srs_config->get_mw_sleep_ms(req->vhost));
+    realtime = _srs_config->get_realtime_enabled(req->vhost);
     
     while (true) {
         // to use isolate thread to recv, can improve about 33% performance.
@@ -599,9 +623,15 @@ int SrsRtmpConn::do_playing(SrsSource* source, SrsQueueRecvThread* trd)
         pithy_print.elapse();
         
 #ifdef SRS_PERF_QUEUE_COND_WAIT
+        // for send wait time debug
+        srs_verbose("send thread now=%"PRId64"us, wait %dms", srs_update_system_time_ms(), mw_sleep);
+        
         // wait for message to incoming.
         // @see https://github.com/winlinvip/simple-rtmp-server/issues/251
-        consumer->wait(SRS_PERF_MW_MIN_MSGS, mw_sleep);
+        consumer->wait(SRS_PERF_MW_MIN_MSGS, mw_sleep, realtime);
+        
+        // for send wait time debug
+        srs_verbose("send thread now=%"PRId64"us wakeup", srs_update_system_time_ms());
 #endif
         
         // get messages from consumer.
@@ -613,10 +643,12 @@ int SrsRtmpConn::do_playing(SrsSource* source, SrsQueueRecvThread* trd)
         }
         
 #ifdef SRS_PERF_QUEUE_COND_WAIT
-        // we use wait to get messages, so the count must be positive.
-        srs_assert(count > 0);
-        srs_info("mw wait %dms and got %d msgs %"PRId64"-%"PRId64"ms", 
-            mw_sleep, count, msgs.msgs[0]->timestamp, msgs.msgs[count - 1]->timestamp);
+        // we use wait timeout to get messages,
+        // for min latency event no message incoming,
+        // so the count maybe zero.
+        srs_verbose("mw wait %dms and got %d msgs %"PRId64"-%"PRId64"ms", mw_sleep, count, 
+            (count > 0? msgs.msgs[0]->timestamp : 0), 
+            (count > 0? msgs.msgs[count - 1]->timestamp : 0));
 #else
         if (count <= 0) {
             srs_info("mw sleep %dms for no msg", mw_sleep);
@@ -1037,12 +1069,12 @@ void SrsRtmpConn::change_mw_sleep(int sleep_ms)
     }
     getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &nb_sbuf, &sock_buf_size);
     
-    srs_trace("mw changed sleep %d=>%d, max_msgs=%d, esbuf=%d, sbuf %d=>%d", 
+    srs_trace("mw changed sleep %d=>%d, max_msgs=%d, esbuf=%d, sbuf %d=>%d, realtime=%d", 
         mw_sleep, sleep_ms, SRS_PERF_MW_MSGS, socket_buffer_size,
-        onb_sbuf, nb_sbuf);
+        onb_sbuf, nb_sbuf, realtime);
 #else
-    srs_trace("mw changed sleep %d=>%d, max_msgs=%d, sbuf %d", 
-        mw_sleep, sleep_ms, SRS_PERF_MW_MSGS, onb_sbuf);
+    srs_trace("mw changed sleep %d=>%d, max_msgs=%d, sbuf %d, realtime=%d", 
+        mw_sleep, sleep_ms, SRS_PERF_MW_MSGS, onb_sbuf, realtime);
 #endif
         
     mw_sleep = sleep_ms;
diff --git a/trunk/src/app/srs_app_rtmp_conn.hpp b/trunk/src/app/srs_app_rtmp_conn.hpp
index 07c77e14df..ecfd0c3cf8 100644
--- a/trunk/src/app/srs_app_rtmp_conn.hpp
+++ b/trunk/src/app/srs_app_rtmp_conn.hpp
@@ -75,6 +75,9 @@ class SrsRtmpConn : public virtual SrsConnection, public virtual ISrsReloadHandl
     int mw_sleep;
     // the MR(merged-write) only enabled for play.
     int mw_enabled;
+    // for realtime
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/257
+    bool realtime;
 public:
     SrsRtmpConn(SrsServer* srs_server, st_netfd_t client_stfd);
     virtual ~SrsRtmpConn();
@@ -86,6 +89,7 @@ class SrsRtmpConn : public virtual SrsConnection, public virtual ISrsReloadHandl
 public:
     virtual int on_reload_vhost_removed(std::string vhost);
     virtual int on_reload_vhost_mw(std::string vhost);
+    virtual int on_reload_vhost_realtime(std::string vhost);
 // interface IKbpsDelta
 public:
     virtual int64_t get_send_bytes_delta();
diff --git a/trunk/src/app/srs_app_source.cpp b/trunk/src/app/srs_app_source.cpp
index 68f960adde..753feafec5 100644
--- a/trunk/src/app/srs_app_source.cpp
+++ b/trunk/src/app/srs_app_source.cpp
@@ -493,7 +493,7 @@ int SrsConsumer::dump_packets(SrsMessageArray* msgs, int& count)
 }
 
 #ifdef SRS_PERF_QUEUE_COND_WAIT
-void SrsConsumer::wait(int nb_msgs, int duration)
+void SrsConsumer::wait(int nb_msgs, int duration, bool realtime)
 {
     mw_min_msgs = nb_msgs;
     mw_duration = duration;
@@ -508,8 +508,15 @@ void SrsConsumer::wait(int nb_msgs, int duration)
     
     // the enqueue will notify this cond.
     mw_waiting = true;
-    // wait for msgs to incoming.
-    st_cond_wait(mw_wait);
+    
+    // use timeout wait for realtime mode.
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/257
+    if (realtime) {
+        st_cond_timedwait(mw_wait, duration * 1000);
+    } else {
+        // use cond block wait for high performance mode.
+        st_cond_wait(mw_wait);
+    }
 }
 #endif
 
diff --git a/trunk/src/app/srs_app_source.hpp b/trunk/src/app/srs_app_source.hpp
index 0a8a7672c2..f0607dccf4 100644
--- a/trunk/src/app/srs_app_source.hpp
+++ b/trunk/src/app/srs_app_source.hpp
@@ -245,8 +245,9 @@ class SrsConsumer
     * wait for messages incomming, atleast nb_msgs and in duration.
     * @param nb_msgs the messages count to wait.
     * @param duration the messgae duration to wait.
+    * @param realtime whether use realtime mode.
     */
-    virtual void wait(int nb_msgs, int duration);
+    virtual void wait(int nb_msgs, int duration, bool realtime);
 #endif
     /**
     * when client send the pause message.
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 1fc98e048a..3db2fb46fa 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    69
+#define VERSION_REVISION    70
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
 #define RTMP_SIG_SRS_ROLE "origin/edge server"
diff --git a/trunk/src/core/srs_core_performance.hpp b/trunk/src/core/srs_core_performance.hpp
index 4439047d24..f2479520ab 100644
--- a/trunk/src/core/srs_core_performance.hpp
+++ b/trunk/src/core/srs_core_performance.hpp
@@ -128,6 +128,15 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #ifdef SRS_PERF_QUEUE_COND_WAIT
     #define SRS_PERF_MW_MIN_MSGS 8
 #endif
+/**
+* the default value of vhost for
+* SRS whether use the min latency mode.
+* for min latence mode:
+* 1. disable the mr for vhost.
+* 2. use timeout for cond wait for consumer queue.
+* @see https://github.com/winlinvip/simple-rtmp-server/issues/257
+*/
+#define SRS_PERF_MIN_LATENCY_ENABLED true
 
 /**
 * how many chunk stream to cache, [0, N].
diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index d51e594728..7696676948 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -61,13 +61,13 @@ int64_t srs_get_system_startup_time_ms()
     
     return _srs_system_time_startup_time / 1000;
 }
-void srs_update_system_time_ms()
+int64_t srs_update_system_time_ms()
 {
     timeval now;
     
     if (gettimeofday(&now, NULL) < 0) {
         srs_warn("gettimeofday failed, ignore");
-        return;
+        return -1;
     }
 
     // @see: https://github.com/winlinvip/simple-rtmp-server/issues/35
@@ -83,7 +83,7 @@ void srs_update_system_time_ms()
     if (_srs_system_time_us_cache <= 0) {
         _srs_system_time_us_cache = now_us;
         _srs_system_time_startup_time = now_us;
-        return;
+        return _srs_system_time_us_cache;
     }
     
     // use relative time.
@@ -99,6 +99,8 @@ void srs_update_system_time_ms()
     _srs_system_time_us_cache = now_us;
     srs_info("system time updated, startup=%"PRId64"us, now=%"PRId64"us", 
         _srs_system_time_startup_time, _srs_system_time_us_cache);
+    
+    return _srs_system_time_us_cache;
 }
 
 string srs_dns_resolve(string host)
diff --git a/trunk/src/kernel/srs_kernel_utility.hpp b/trunk/src/kernel/srs_kernel_utility.hpp
index 706a7e6811..8bb6f179a9 100644
--- a/trunk/src/kernel/srs_kernel_utility.hpp
+++ b/trunk/src/kernel/srs_kernel_utility.hpp
@@ -40,7 +40,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 extern int64_t srs_get_system_time_ms();
 extern int64_t srs_get_system_startup_time_ms();
 // the deamon st-thread will update it.
-extern void srs_update_system_time_ms();
+extern int64_t srs_update_system_time_ms();
 
 // dns resolve utility, return the resolved ip address.
 extern std::string srs_dns_resolve(std::string host);