diff --git a/trunk/research/msg_zerocopy/.gitignore b/trunk/research/msg_zerocopy/.gitignore
new file mode 100644
index 000000000..3ddc9a018
--- /dev/null
+++ b/trunk/research/msg_zerocopy/.gitignore
@@ -0,0 +1,2 @@
+server
+client
\ No newline at end of file
diff --git a/trunk/research/msg_zerocopy/Makefile b/trunk/research/msg_zerocopy/Makefile
new file mode 100644
index 000000000..628939550
--- /dev/null
+++ b/trunk/research/msg_zerocopy/Makefile
@@ -0,0 +1,8 @@
+
+default: server client
+
+server: server.cpp ../../objs/st/libst.a
+	gcc -g -O0 -I../../objs/st/ $^ -o $@
+
+client: client.cpp ../../objs/st/libst.a
+	gcc -g -O0 -I../../objs/st/ $^ -o $@
diff --git a/trunk/research/msg_zerocopy/client.cpp b/trunk/research/msg_zerocopy/client.cpp
new file mode 100644
index 000000000..c30f3584d
--- /dev/null
+++ b/trunk/research/msg_zerocopy/client.cpp
@@ -0,0 +1,61 @@
+#include <st.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv)
+{
+    if (argc < 3) {
+        printf("Usage: %s <host> <port>\n", argv[0]);
+        printf("For example:\n");
+        printf("        %s 127.0.0.1 8000\n", argv[0]);
+        exit(-1);
+    }
+
+    assert(!st_set_eventsys(ST_EVENTSYS_ALT));
+    assert(!st_init());
+
+    int fd = socket(PF_INET, SOCK_DGRAM, 0);
+    assert(fd > 0);
+
+    st_netfd_t stfd = st_netfd_open_socket(fd);
+    assert(stfd);
+
+    sockaddr_in peer;
+    memset(&peer, 0, sizeof(sockaddr_in));
+
+    int port = 8000;
+    const char* host = "127.0.0.1";
+    peer.sin_family = AF_INET;
+    peer.sin_port = htons(port);
+    peer.sin_addr.s_addr = inet_addr(host);
+
+    char buf[1500];
+    memset(buf, 0, sizeof(buf));
+    memcpy(buf, "Hello", 5);
+
+    iovec iov;
+    iov.iov_base = buf;
+    iov.iov_len = strlen(buf);
+
+    msghdr msg;
+    memset(&msg, 0, sizeof(msghdr));
+    msg.msg_name = (sockaddr_in*)&peer;
+    msg.msg_namelen = sizeof(sockaddr_in);
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+
+    int r0 = st_sendmsg(stfd, &msg, 0, ST_UTIME_NO_TIMEOUT);
+    printf("Ping %s:%d %d bytes, r0=%d, %s\n", host, port, iov.iov_len, r0, msg.msg_iov->iov_base);
+
+    r0 = st_recvmsg(stfd, &msg, 0, ST_UTIME_NO_TIMEOUT);
+    assert(r0 > 0);
+    printf("From %s:%d %d bytes, flags %#x, %s\n", inet_ntoa(peer.sin_addr), ntohs(peer.sin_port), r0,
+        msg.msg_flags, msg.msg_iov->iov_base);
+
+    return 0;
+}
diff --git a/trunk/research/msg_zerocopy/server.cpp b/trunk/research/msg_zerocopy/server.cpp
new file mode 100644
index 000000000..cc1259680
--- /dev/null
+++ b/trunk/research/msg_zerocopy/server.cpp
@@ -0,0 +1,79 @@
+#include <st.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv)
+{
+    if (argc < 3) {
+        printf("Usage: %s <host> <port>\n", argv[0]);
+        printf("For example:\n");
+        printf("        %s 0.0.0.0 8000\n", argv[0]);
+        exit(-1);
+    }
+
+    assert(!st_set_eventsys(ST_EVENTSYS_ALT));
+    assert(!st_init());
+
+    int fd = socket(PF_INET, SOCK_DGRAM, 0);
+    assert(fd > 0);
+
+    int n = 1;
+    int r0 = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&n, sizeof(n));
+    assert(!r0);
+
+    sockaddr_in addr;
+    memset(&addr, 0, sizeof(sockaddr_in));
+
+    int port = 8000;
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+    addr.sin_addr.s_addr = inet_addr("0.0.0.0");
+
+    r0 = bind(fd, (sockaddr *)&addr, sizeof(sockaddr_in));
+    assert(!r0);
+
+    st_netfd_t stfd = st_netfd_open_socket(fd);
+    assert(stfd);
+
+    printf("Listen at udp://%d\n", port);
+
+    msghdr msg;
+    memset(&msg, 0, sizeof(msghdr));
+
+    sockaddr_in peer;
+    memset(&peer, 0, sizeof(sockaddr_in));
+    msg.msg_name = (sockaddr_in*)&peer;
+    msg.msg_namelen = sizeof(sockaddr_in);
+
+    char buf[1500];
+    memset(buf, 0, sizeof(buf));
+
+    iovec iov;
+    memset(&iov, 0, sizeof(iovec));
+    iov.iov_base = buf;
+    iov.iov_len = sizeof(buf);
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+
+    while (true) {
+        r0 = st_recvmsg(stfd, &msg, 0, ST_UTIME_NO_TIMEOUT);
+        assert(r0 > 0);
+        printf("From %s:%d %d bytes, flags %#x, %s\n", inet_ntoa(peer.sin_addr), ntohs(peer.sin_port), r0,
+            msg.msg_flags, msg.msg_iov->iov_base);
+
+        memcpy(msg.msg_iov->iov_base, "World", 5);
+        msg.msg_iov->iov_len = 5;
+
+        r0 = st_sendmsg(stfd, &msg, 0, ST_UTIME_NO_TIMEOUT);
+        assert(r0 > 0);
+        printf("Pong %s:%d %d bytes, flags %#x, %s\n", inet_ntoa(peer.sin_addr), ntohs(peer.sin_port), r0,
+            msg.msg_flags, msg.msg_iov->iov_base);
+    }
+
+    return 0;
+}