diff --git a/README.md b/README.md
index 9c5c9593f..a5ca1f7dc 100755
--- a/README.md
+++ b/README.md
@@ -48,6 +48,7 @@ url: rtmp://127.0.0.1:1935/live/livestream
 * nginx v1.5.0: 139524 lines <br/>
 
 ### History
+* v0.4, 2013-11-09, support config the chunk_size.
 * v0.4, 2013-11-09, support pause for live stream.
 * v0.3, 2013-11-04, v0.3 released. 11773 lines.
 * v0.3, 2013-11-04, support refer/play-refer/publish-refer.
diff --git a/trunk/conf/srs.conf b/trunk/conf/srs.conf
index df5c00f38..9066be600 100755
--- a/trunk/conf/srs.conf
+++ b/trunk/conf/srs.conf
@@ -1,12 +1,23 @@
+# the listen ports, split by space.
 listen 1935 19350;
+# the default chunk size is 128, max is 65536,
+# some client does not support chunk size change,
+# however, most clients supports it and it can improve 
+# performance about 10%.
+# if not specified, set to 4096.
+chunk_size 65000;
+# vhost list, the __defaultVhost__ is the default vhost
+# for which cannot identify the required vhost.
 vhost __defaultVhost__ {
 }
+# the vhost disabled.
 vhost removed.vhost.com {
     # whether the vhost is enabled.
     # if off, all request access denied.
     # default: on
     enabled         off;
 }
+# the vhost for min delay, donot cache any stream.
 vhost min.delay.com {
     # whether cache the last gop.
     # if on, cache the last gop and dispatch to client,
@@ -18,6 +29,7 @@ vhost min.delay.com {
     # default: on
     gop_cache       off;
 }
+# the vhost for antisuck.
 vhost refer.anti_suck.com {
     # the common refer for play and publish.
     # if the page url of client not in the refer, access denied.
diff --git a/trunk/src/core/srs_core_client.cpp b/trunk/src/core/srs_core_client.cpp
index cf64c7299..ebcc9e541 100755
--- a/trunk/src/core/srs_core_client.cpp
+++ b/trunk/src/core/srs_core_client.cpp
@@ -24,6 +24,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core_client.hpp>
 
 #include <arpa/inet.h>
+#include <stdlib.h>
 
 #include <srs_core_error.hpp>
 #include <srs_core_log.hpp>
@@ -135,20 +136,23 @@ int SrsClient::do_cycle()
 	req->strip();
 	srs_trace("identify client success. type=%d, stream_name=%s", type, req->stream.c_str());
 	
-	// TODO: read from config.
 	int chunk_size = 4096;
+	SrsConfDirective* conf = config->get_chunk_size();
+	if (conf && !conf->arg0().empty()) {
+		chunk_size = ::atoi(conf->arg0().c_str());
+	}
 	if ((ret = rtmp->set_chunk_size(chunk_size)) != ERROR_SUCCESS) {
-		srs_error("set chunk size failed. ret=%d", ret);
+		srs_error("set chunk_size=%d failed. ret=%d", chunk_size, ret);
 		return ret;
 	}
-	srs_verbose("set chunk size success");
+	srs_trace("set chunk_size=%d success", chunk_size);
 	
 	// find a source to publish.
 	SrsSource* source = SrsSource::find(req->get_stream_url());
 	srs_assert(source != NULL);
 	
-	SrsConfDirective* conf = config->get_gop_cache(req->vhost);
 	bool enabled_cache = true;
+	conf = config->get_gop_cache(req->vhost);
 	if (conf && conf->arg0() == "off") {
 		enabled_cache = false;
 	}
diff --git a/trunk/src/core/srs_core_config.cpp b/trunk/src/core/srs_core_config.cpp
index 3a183e14b..d366a09f4 100755
--- a/trunk/src/core/srs_core_config.cpp
+++ b/trunk/src/core/srs_core_config.cpp
@@ -536,6 +536,11 @@ SrsConfDirective* Config::get_listen()
 	return root->get("listen");
 }
 
+SrsConfDirective* Config::get_chunk_size()
+{
+	return root->get("chunk_size");
+}
+
 int Config::parse_argv(int& i, char** argv)
 {
 	int ret = ERROR_SUCCESS;
diff --git a/trunk/src/core/srs_core_config.hpp b/trunk/src/core/srs_core_config.hpp
index 189e8411e..3baa0a11c 100755
--- a/trunk/src/core/srs_core_config.hpp
+++ b/trunk/src/core/srs_core_config.hpp
@@ -102,6 +102,7 @@ public:
 	virtual SrsConfDirective* get_refer_play(std::string vhost);
 	virtual SrsConfDirective* get_refer_publish(std::string vhost);
 	virtual SrsConfDirective* get_listen();
+	virtual SrsConfDirective* get_chunk_size();
 private:
 	virtual int parse_argv(int& i, char** argv);
 	virtual void print_help(char** argv);