2 files changed, 159 insertions, 0 deletions
diff --git a/host/lib/transport/CMakeLists.txt b/host/lib/transport/CMakeLists.txt
index 79c8a90b7..db21b9f8e 100644
--- a/host/lib/transport/CMakeLists.txt
+++ b/host/lib/transport/CMakeLists.txt
@@ -122,6 +122,7 @@ LIBUHD_PYTHON_GEN_SOURCE(
 )
 
 LIBUHD_APPEND_SOURCES(
+    ${CMAKE_CURRENT_SOURCE_DIR}/zero_copy_recv_offload.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/tcp_zero_copy.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/buffer_pool.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/if_addrs.cpp
diff --git a/host/lib/transport/zero_copy_recv_offload.cpp b/host/lib/transport/zero_copy_recv_offload.cpp
new file mode 100644
index 000000000..e8b013abc
--- /dev/null
+++ b/host/lib/transport/zero_copy_recv_offload.cpp
@@ -0,0 +1,158 @@
+//
+// Copyright 2016 Ettus Research
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/transport/zero_copy_recv_offload.hpp>
+#include <uhd/transport/bounded_buffer.hpp>
+#include <uhd/transport/buffer_pool.hpp>
+#include <uhd/utils/msg.hpp>
+#include <uhd/utils/log.hpp>
+#include <uhd/utils/safe_call.hpp>
+#include <boost/format.hpp>
+#include <boost/make_shared.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/thread.hpp>
+#include <boost/bind.hpp>
+
+using namespace uhd;
+using namespace uhd::transport;
+
+typedef bounded_buffer<managed_recv_buffer::sptr> bounded_buffer_t;
+
+/***********************************************************************
+ * Zero copy offload transport:
+ * An intermediate transport that utilizes threading to free
+ * the main thread from any receive work.
+ **********************************************************************/
+class zero_copy_recv_offload_impl : public zero_copy_recv_offload {
+public:
+    typedef boost::shared_ptr<zero_copy_recv_offload_impl> sptr;
+
+    zero_copy_recv_offload_impl(zero_copy_if::sptr transport,
+                          const double timeout) :
+        _transport(transport), _timeout(timeout),
+        _inbox(transport->get_num_recv_frames()),
+        _recv_done(false)
+    {
+        UHD_LOG << "Created threaded transport" << std::endl;
+
+        // Create the receive and send threads to offload
+        // the system calls onto other threads
+        _recv_thread = boost::thread(
+            boost::bind(&zero_copy_recv_offload_impl::enqueue_recv, this)
+        );
+    }
+
+    // Receive thread flags
+    void set_recv_done()
+    {
+        boost::lock_guard<boost::mutex> guard(_recv_mutex);
+        _recv_done = true;
+    }
+
+    bool is_recv_done()
+    {
+        boost::lock_guard<boost::mutex> guard(_recv_mutex);
+        return _recv_done;
+    }
+
+    ~zero_copy_recv_offload_impl()
+    {
+        // Signal the threads we're finished
+        set_recv_done();
+
+        // Wait for them to join
+        UHD_SAFE_CALL(
+            _recv_thread.join();
+        )
+    }
+
+    // The receive thread function is responsible for
+    // pulling pointers to managed receiver buffers quickly
+    void enqueue_recv()
+    {
+        while (not is_recv_done()) {
+            managed_recv_buffer::sptr buff = _transport->get_recv_buff(_timeout);
+            if (not buff) continue;
+            _inbox.push_with_timed_wait(buff, _timeout);
+        }
+    }
+
+    /*******************************************************************
+     * Receive implementation:
+     * Pop the receive buffer pointer from the underlying transport
+     ******************************************************************/
+    managed_recv_buffer::sptr get_recv_buff(double timeout)
+    {
+        managed_recv_buffer::sptr ptr;
+        _inbox.pop_with_timed_wait(ptr, timeout);
+        return ptr;
+    }
+
+    size_t get_num_recv_frames() const
+    {
+        return _transport->get_num_recv_frames();
+    }
+
+    size_t get_recv_frame_size() const
+    {
+        return _transport->get_recv_frame_size();
+    }
+
+    /*******************************************************************
+     * Send implementation:
+     * Pass the send buffer pointer from the underlying transport
+     ******************************************************************/
+    managed_send_buffer::sptr get_send_buff(double timeout)
+    {
+        return _transport->get_send_buff(timeout);
+    }
+
+    size_t get_num_send_frames() const
+    {
+        return _transport->get_num_send_frames();
+    }
+
+    size_t get_send_frame_size() const
+    {
+        return _transport->get_send_frame_size();
+    }
+
+private:
+    // The linked transport
+    zero_copy_if::sptr _transport;
+
+    const double _timeout;
+
+    // Shared buffers
+    bounded_buffer_t _inbox;
+
+    // Threading
+    bool _recv_done;
+    boost::thread _recv_thread;
+    boost::mutex  _recv_mutex;
+};
+
+zero_copy_recv_offload::sptr zero_copy_recv_offload::make(
+        zero_copy_if::sptr transport,
+        const double timeout)
+{
+    zero_copy_recv_offload_impl::sptr zero_copy_recv_offload(
+        new zero_copy_recv_offload_impl(transport, timeout)
+    );
+
+    return zero_copy_recv_offload;
+}