diff --git a/src/mm_io.c b/src/mm_io.c
index 0ca1af1c..ddae3f1f 100644
--- a/src/mm_io.c
+++ b/src/mm_io.c
@@ -23,10 +23,7 @@ machine_create_io(machine_t obj)
 	io->machine = machine;
 
 	/* read */
-	/*
-	mm_buf_init(&io->read_ahead);
-	io->read_ahead_size = 16384;
-	*/
+	mm_buf_init(&io->readahead_buf);
 
 #if 0
 	/* getaddrinfo */
@@ -46,7 +43,7 @@ MACHINE_API void
 machine_free_io(machine_io_t obj)
 {
 	mm_io_t *io = obj;
-	/*mm_buf_free(&io->read_ahead);*/
+	mm_buf_free(&io->readahead_buf);
 	free(io);
 }
 
@@ -108,22 +105,6 @@ machine_set_keepalive(machine_io_t obj, int enable, int delay)
 	return 0;
 }
 
-MACHINE_API int
-machine_set_readahead(machine_io_t obj, int size)
-{
-	mm_io_t *io = obj;
-	/*
-	if (mm_buf_size(&io->read_ahead) > 0) {
-		mm_io_set_errno(io, EINPROGRESS);
-		return -1;
-	}
-	io->read_ahead_size = size;
-	*/
-	(void)io;
-	(void)size;
-	return 0;
-}
-
 int mm_io_socket_set(mm_io_t *io, int fd)
 {
 	io->fd = fd;
diff --git a/src/mm_io.h b/src/mm_io.h
index cb4240b1..0c671c42 100644
--- a/src/mm_io.h
+++ b/src/mm_io.h
@@ -54,6 +54,10 @@ struct mm_io_t {
 	int               read_eof;
 	int               read_status;
 	mm_fiber_t       *read_fiber;
+	mm_buf_t          readahead_buf;
+	int               readahead_pos;
+	int               readahead_pos_read;
+	int               readahead_size;
 
 	/*
 	mm_timer_t        read_timer;
diff --git a/src/mm_read.c b/src/mm_read.c
index 6907da29..e78acdc6 100644
--- a/src/mm_read.c
+++ b/src/mm_read.c
@@ -63,31 +63,16 @@ wakeup:
 	return 0;
 }
 
-int
-mm_read(mm_io_t *io, char *buf, int size, uint64_t time_ms)
+static int
+mm_read_default(mm_io_t *io, uint64_t time_ms)
 {
 	mm_t *machine = machine = io->machine;
 	mm_fiber_t *current = mm_scheduler_current(&io->machine->scheduler);
-	mm_io_set_errno(io, 0);
-	if (mm_fiber_is_cancelled(current)) {
-		mm_io_set_errno(io, ECANCELED);
-		return -1;
-	}
-	if (io->read_fiber) {
-		mm_io_set_errno(io, EINPROGRESS);
-		return -1;
-	}
-	if (! io->connected) {
-		mm_io_set_errno(io, ENOTCONN);
-		return -1;
-	}
-	io->read_status   = 0;
-	io->read_timedout = 0;
-	io->read_eof      = 0;
-	io->read_fiber    = NULL;
-	io->read_size     = size;
-	io->read_pos      = 0;
-	io->read_buf      = buf;
+
+	io->read_status = 0;
+	io->read_eof    = 0;
+	io->read_fiber  = NULL;
+	io->read_pos    = 0;
 
 	io->handle.on_read = mm_read_cb;
 	io->handle.on_read_arg = io;
@@ -126,7 +111,7 @@ mm_read(mm_io_t *io, char *buf, int size, uint64_t time_ms)
 
 	rc = io->read_status;
 	if (rc == 0) {
-		if (io->read_pos != size) {
+		if (io->read_pos != io->read_size) {
 			mm_io_set_errno(io, ECONNRESET);
 			return -1;
 		}
@@ -136,6 +121,181 @@ mm_read(mm_io_t *io, char *buf, int size, uint64_t time_ms)
 	return -1;
 }
 
+static int
+mm_readahead_read(mm_io_t *io, uint64_t time_ms);
+
+int mm_readahead_stop(mm_io_t *io);
+
+static int
+mm_readahead_cb(mm_fd_t *handle)
+{
+	mm_io_t *io = handle->on_read_arg;
+	mm_t *machine = machine = io->machine;
+
+	int left = io->readahead_size - io->readahead_pos;
+	int rc;
+	while (left > 0)
+	{
+		rc = mm_socket_read(io->fd, io->readahead_buf.start + io->readahead_pos, left);
+		if (rc == -1) {
+			if (errno == EAGAIN ||
+			    errno == EWOULDBLOCK)
+				break;
+			if (errno == EINTR)
+				continue;
+			io->read_status = errno;
+			if (io->read_fiber)
+				mm_scheduler_wakeup(io->read_fiber);
+			return 0;
+		}
+		io->readahead_pos += rc;
+		left = io->readahead_size - io->readahead_pos;
+		assert(left >= 0);
+		if (rc == 0) {
+			/* eof */
+			mm_readahead_stop(io);
+			io->read_eof = 1;
+			io->read_status = 0;
+			break;
+		}
+	}
+	io->read_status = 0;
+	if (io->read_fiber) {
+		int ra_left = io->readahead_pos - io->readahead_pos_read;
+		if (io->read_eof || ra_left >= io->read_size)
+			mm_scheduler_wakeup(io->read_fiber);
+	}
+	return 0;
+}
+
+int
+mm_readahead_start(mm_io_t *io)
+{
+	mm_t *machine = machine = io->machine;
+	int rc;
+	rc = mm_loop_read(&machine->loop, &io->handle, mm_readahead_cb, io, 1);
+	if (rc == -1) {
+		mm_io_set_errno(io, errno);
+		return -1;
+	}
+	return 0;
+}
+
+int
+mm_readahead_stop(mm_io_t *io)
+{
+	mm_t *machine = machine = io->machine;
+	int rc;
+	rc = mm_loop_read(&machine->loop, &io->handle, NULL, NULL, 0);
+	if (rc == -1) {
+		mm_io_set_errno(io, errno);
+		return -1;
+	}
+	return 0;
+}
+
+static int
+mm_readahead_read(mm_io_t *io, uint64_t time_ms)
+{
+	mm_t *machine = machine = io->machine;
+	mm_fiber_t *current = mm_scheduler_current(&io->machine->scheduler);
+
+	if (io->read_size > io->readahead_size) {
+		mm_io_set_errno(io, EINVAL);
+		return -1;
+	}
+
+	/* try to use readahead first */
+	assert(io->readahead_pos >= io->readahead_pos_read);
+	int ra_left = io->readahead_pos - io->readahead_pos_read;
+	if (ra_left >= io->read_size) {
+		memcpy(io->read_buf, io->readahead_buf.start + io->readahead_pos_read,
+		       io->read_size);
+		io->readahead_pos_read += io->read_size;
+		return 0;
+	}
+
+	if (io->read_status != 0) {
+		mm_io_set_errno(io, io->read_status);
+		return -1;
+	}
+
+	if (io->read_eof) {
+		mm_io_set_errno(io, ECONNRESET);
+		return -1;
+	}
+
+	/* copy first readahead chunk */
+	int copy_pos = 0;
+	if (ra_left > 0) {
+		memcpy(io->read_buf,
+		       io->readahead_buf.start + io->readahead_pos_read,
+		       ra_left);
+		io->readahead_pos_read += ra_left;
+		io->read_size -= ra_left;
+		copy_pos = ra_left;
+	}
+
+	/* reset readahead position */
+	assert(io->readahead_pos_read == io->readahead_pos);
+	io->readahead_pos = 0;
+	io->readahead_pos_read = 0;
+
+	/* wait for timedout, cancel or execution status */
+	mm_timer_start(&machine->loop.clock,
+	               &io->read_timer,
+	               mm_read_timer_cb, io, time_ms);
+	mm_call_begin(&current->call, mm_read_cancel_cb, io);
+	io->read_fiber = current;
+	mm_scheduler_yield(&machine->scheduler);
+	io->read_fiber = NULL;
+	mm_call_end(&current->call);
+	mm_timer_stop(&io->read_timer);
+
+	int rc;
+	rc = io->read_status;
+	if (rc == 0) {
+		ra_left = io->readahead_pos - io->readahead_pos_read;
+		if (ra_left < io->read_size) {
+			mm_io_set_errno(io, ECONNRESET);
+			return -1;
+		}
+		memcpy(io->read_buf + copy_pos,
+		       io->readahead_buf.start + io->readahead_pos_read,
+		       io->read_size);
+		io->readahead_pos_read += io->read_size;
+		return 0;
+	}
+	mm_io_set_errno(io, rc);
+	return -1;
+}
+
+int
+mm_read(mm_io_t *io, char *buf, int size, uint64_t time_ms)
+{
+	mm_t *machine = machine = io->machine;
+	mm_fiber_t *current = mm_scheduler_current(&io->machine->scheduler);
+	mm_io_set_errno(io, 0);
+	if (mm_fiber_is_cancelled(current)) {
+		mm_io_set_errno(io, ECANCELED);
+		return -1;
+	}
+	if (io->read_fiber) {
+		mm_io_set_errno(io, EINPROGRESS);
+		return -1;
+	}
+	if (! io->connected) {
+		mm_io_set_errno(io, ENOTCONN);
+		return -1;
+	}
+	io->read_size     = size;
+	io->read_buf      = buf;
+	io->read_timedout = 0;
+	if (io->readahead_size > 0)
+		return mm_readahead_read(io, time_ms);
+	return mm_read_default(io, time_ms);
+}
+
 MACHINE_API int
 machine_read(machine_io_t obj, char *buf, int size, uint64_t time_ms)
 {
@@ -151,3 +311,42 @@ machine_read_timedout(machine_io_t obj)
 	mm_io_t *io = obj;
 	return io->read_timedout;
 }
+
+MACHINE_API int
+machine_set_readahead(machine_io_t obj, int size)
+{
+	mm_io_t *io = obj;
+	mm_fiber_t *current = mm_scheduler_current(&io->machine->scheduler);
+	mm_io_set_errno(io, 0);
+	if (mm_fiber_is_cancelled(current)) {
+		mm_io_set_errno(io, ECANCELED);
+		return -1;
+	}
+	if (io->read_fiber) {
+		mm_io_set_errno(io, EINPROGRESS);
+		return -1;
+	}
+	if (! io->connected) {
+		mm_io_set_errno(io, ENOTCONN);
+		return -1;
+	}
+	if (size <= 0) {
+		mm_io_set_errno(io, EINVAL);
+		return -1;
+	}
+	if (io->readahead_size > 0) {
+		mm_io_set_errno(io, EINPROGRESS);
+		return -1;
+	}
+	int rc;
+	rc = mm_buf_ensure(&io->readahead_buf, size);
+	if (rc == -1) {
+		mm_io_set_errno(io, ENOMEM);
+		return -1;
+	}
+	rc = mm_readahead_start(io);
+	if (rc == -1)
+		return -1;
+	io->readahead_size = size;
+	return 0;
+}
diff --git a/src/mm_read.h b/src/mm_read.h
index bde4f008..9217f0b2 100644
--- a/src/mm_read.h
+++ b/src/mm_read.h
@@ -9,4 +9,7 @@
 
 int mm_read(mm_io_t*, char*, int, uint64_t);
 
+int mm_readahead_start(mm_io_t*);
+int mm_readahead_stop(mm_io_t*);
+
 #endif
diff --git a/tests/makefile b/tests/makefile
index 97f5b50d..06ea2757 100644
--- a/tests/makefile
+++ b/tests/makefile
@@ -6,7 +6,6 @@ LFLAGS     = $(LFLAGS_LIB)
 TESTS      = test_new \
              test_create \
              test_sleep \
-             test_sleep_2 \
              test_wait \
              test_condition \
              test_condition_2 \
diff --git a/tests/test_client_server_ra.c b/tests/test_client_server_ra.c
index 369bb4fc..5fa7321f 100644
--- a/tests/test_client_server_ra.c
+++ b/tests/test_client_server_ra.c
@@ -77,17 +77,27 @@ client(void *arg)
 	if (rc < 0) {
 		printf("client: connect failed\n");
 		machine_close(client);
+		machine_free_io(client);
 		return;
 	}
 
 	printf("client: connected\n");
 
+	rc = machine_set_readahead(client, 1024);
+	if (rc < 0) {
+		printf("client: %s\n", machine_error(client));
+		machine_close(client);
+		machine_free_io(client);
+		return;
+	}
+
 	/* read and fill readahead buffer */
 	char buf[16];
 	rc = machine_read(client, buf, 11, 0);
 	if (rc < 0) {
 		printf("client: read failed\n");
 		machine_close(client);
+		machine_free_io(client);
 		return;
 	}