rfnoc: examples: Porting examples to new RFNoC

rfnoc_nullsource_ce_rx, rfnoc_rx_to_file:

These examples are modified so they can be run with the new RFNoC API.

test_messages:

Fixes failures in the time test when it is executed immediately after an
underrun test. The DUC considers time specs on a per burst basis, so
when the underrun test leaves a burst unfinished, a time spec on the
next burst is ignored.

3 files changed, 203 insertions, 206 deletions

diff --git a/host/examples/rfnoc_nullsource_ce_rx.cpp b/host/examples/rfnoc_nullsource_ce_rx.cpp
index 7dd21905f..640e5bcff 100644
--- a/host/examples/rfnoc_nullsource_ce_rx.cpp
+++ b/host/examples/rfnoc_nullsource_ce_rx.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright 2014 Ettus Research LLC
+// Copyright 2019 Ettus Research, a National Instruments Brand
 //
 // 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
@@ -22,8 +22,9 @@
 
 #include <uhd/device3.hpp>
 #include <uhd/exception.hpp>
-#include <uhd/rfnoc/block_ctrl.hpp>
-#include <uhd/rfnoc/null_block_ctrl.hpp>
+#include <uhd/rfnoc/block_control.hpp>
+#include <uhd/rfnoc/null_block_control.hpp>
+#include <uhd/rfnoc_graph.hpp>
 #include <uhd/utils/safe_main.hpp>
 #include <uhd/utils/thread.hpp>
 #include <boost/format.hpp>
@@ -48,7 +49,6 @@ template <typename samp_type>
 void recv_to_file(uhd::rx_streamer::sptr rx_stream,
     const std::string& file,
     size_t samps_per_buff,
-    unsigned long long num_requested_samples,
     double time_requested       = 0.0,
     bool bw_summary             = false,
     bool stats                  = false,
@@ -65,10 +65,8 @@ void recv_to_file(uhd::rx_streamer::sptr rx_stream,
     bool overflow_message = true;
 
     // setup streaming
-    uhd::stream_cmd_t stream_cmd((num_requested_samples == 0)
-                                     ? uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS
-                                     : uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);
-    stream_cmd.num_samps  = num_requested_samples;
+    uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS);
+    stream_cmd.num_samps  = 0;
     stream_cmd.stream_now = true;
     stream_cmd.time_spec  = uhd::time_spec_t();
     std::cout << "Issuing start stream cmd" << std::endl;
@@ -85,7 +83,6 @@ void recv_to_file(uhd::rx_streamer::sptr rx_stream,
     unsigned long long last_update_samps = 0;
 
     while (not stop_signal_called
-           and (num_requested_samples != num_total_samps or num_requested_samples == 0)
            and (time_requested == 0.0 or std::chrono::steady_clock::now() <= stop_time)) {
         const auto now = std::chrono::steady_clock::now();
 
@@ -207,9 +204,9 @@ void pretty_print_flow_graph(std::vector<std::string> blocks)
 int UHD_SAFE_MAIN(int argc, char* argv[])
 {
     // variables to be set by po
-    std::string args, file, format, nullid, blockid, blockid2;
-    size_t total_num_samps, spb, spp;
-    double rate, total_time, setup_time, block_rate;
+    std::string args, file, format, nullid;
+    size_t spb, spp, throttle_cycles;
+    double rate, total_time;
 
     // setup the program options
     po::options_description desc("Allowed options");
@@ -217,22 +214,18 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
     desc.add_options()
         ("help", "help message")
         ("args", po::value<std::string>(&args)->default_value("type=x300"), "multi uhd device address args")
-        ("file", po::value<std::string>(&file)->default_value("usrp_samples.dat"), "name of the file to write binary samples to, set to stdout to print")
+        ("file", po::value<std::string>(&file)->default_value("graph_samples.dat"), "name of the file to write binary samples to, set to stdout to print")
         ("null", "run without writing to file")
-        ("nsamps", po::value<size_t>(&total_num_samps)->default_value(0), "total number of samples to receive")
         ("time", po::value<double>(&total_time)->default_value(0), "total number of seconds to receive")
         ("spb", po::value<size_t>(&spb)->default_value(10000), "samples per buffer")
         ("spp", po::value<size_t>(&spp)->default_value(64), "samples per packet (on FPGA and wire)")
-        ("block_rate", po::value<double>(&block_rate)->default_value(160e6), "The clock rate of the processing block.")
+        ("throttle-cycles", po::value<size_t>(&throttle_cycles)->default_value(0), "Number of cycles to force in between packets")
         ("rate", po::value<double>(&rate)->default_value(1e6), "rate at which samples are produced in the null source")
-        ("setup", po::value<double>(&setup_time)->default_value(1.0), "seconds of setup time")
         ("format", po::value<std::string>(&format)->default_value("sc16"), "File sample type: sc16, fc32, or fc64")
         ("progress", "periodically display short-term bandwidth")
         ("stats", "show average bandwidth on exit")
         ("continue", "don't abort on a bad packet")
-        ("nullid", po::value<std::string>(&nullid)->default_value("0/NullSrcSink_0"), "The block ID for the null source.")
-        ("blockid", po::value<std::string>(&blockid)->default_value("FIFO"), "The block ID for the processing block.")
-        ("blockid2", po::value<std::string>(&blockid2)->default_value(""), "Optional: The block ID for the 2nd processing block.")
+        ("nullid", po::value<std::string>(&nullid)->default_value("0/NullSrcSink#0"), "The block ID for the null source.")
     ;
     // clang-format on
     po::variables_map vm;
@@ -256,36 +249,16 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
         std::cout << "Must specify a valid block ID for the null source." << std::endl;
         return ~0;
     }
-    if (not uhd::rfnoc::block_id_t::is_valid_block_id(blockid)) {
-        std::cout << "Must specify a valid block ID for the processing block."
-                  << std::endl;
-        return ~0;
-    }
-    if (not blockid2.empty()) {
-        if (not uhd::rfnoc::block_id_t::is_valid_block_id(blockid2)) {
-            std::cout << "Invalid block ID for the 2nd processing block." << std::endl;
-            return ~0;
-        }
-    }
 
     // Set up SIGINT handler. For indefinite streaming, display info on how to stop.
     std::signal(SIGINT, &sig_int_handler);
-    if (total_num_samps == 0) {
-        std::cout << "Press Ctrl + C to stop streaming..." << std::endl;
-    }
 
     /////////////////////////////////////////////////////////////////////////
     //////// 1. Setup a USRP device /////////////////////////////////////////
     /////////////////////////////////////////////////////////////////////////
     std::cout << std::endl;
     std::cout << "Creating the USRP device with args: " << args << std::endl;
-    uhd::device3::sptr usrp = uhd::device3::make(args);
-
-    std::this_thread::sleep_for( // allow for some setup time
-        std::chrono::milliseconds(int64_t(setup_time * 1000)));
-    // Reset device streaming state
-    usrp->clear();
-    uhd::rfnoc::graph::sptr rx_graph = usrp->create_graph("rx_graph");
+    uhd::rfnoc::rfnoc_graph::sptr graph = uhd::rfnoc::rfnoc_graph::make(args);
 
     /////////////////////////////////////////////////////////////////////////
     //////// 2. Get block control objects ///////////////////////////////////
@@ -293,28 +266,16 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
     std::vector<std::string> blocks;
 
     // For the null source control, we want to use the subclassed access,
-    // so we create a null_block_ctrl:
-    uhd::rfnoc::null_block_ctrl::sptr null_src_ctrl;
-    if (usrp->has_block<uhd::rfnoc::null_block_ctrl>(nullid)) {
-        null_src_ctrl = usrp->get_block_ctrl<uhd::rfnoc::null_block_ctrl>(nullid);
+    // so we create a null_block_control:
+    uhd::rfnoc::null_block_control::sptr null_src_ctrl;
+    if (graph->has_block<uhd::rfnoc::null_block_control>(nullid)) {
+        null_src_ctrl = graph->get_block<uhd::rfnoc::null_block_control>(nullid);
         blocks.push_back(null_src_ctrl->get_block_id());
     } else {
         std::cout << "Error: Device has no null block." << std::endl;
         return ~0;
     }
 
-    // For the processing blocks, we don't care what type the block is,
-    // so we make it a block_ctrl_base (default):
-    uhd::rfnoc::block_ctrl_base::sptr proc_block_ctrl, proc_block_ctrl2;
-    if (usrp->has_block(blockid)) {
-        proc_block_ctrl = usrp->get_block_ctrl(blockid);
-        blocks.push_back(proc_block_ctrl->get_block_id());
-    }
-    if (not blockid2.empty() and usrp->has_block(blockid2)) {
-        proc_block_ctrl2 = usrp->get_block_ctrl(blockid2);
-        blocks.push_back(proc_block_ctrl2->get_block_id());
-    }
-
     blocks.push_back("HOST");
     pretty_print_flow_graph(blocks);
 
@@ -322,77 +283,52 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
     //////// 3. Set channel definitions /////////////////////////////////////
     /////////////////////////////////////////////////////////////////////////
     uhd::device_addr_t stream_args_args;
-    //
-    // Here, we define that there is only 1 channel, and it points
-    // to the final processing block.
-    if (proc_block_ctrl2 and proc_block_ctrl) {
-        stream_args_args["block_id"] = blockid2;
-    } else if (proc_block_ctrl) {
-        stream_args_args["block_id"] = blockid;
-    } else {
-        stream_args_args["block_id"] = nullid;
-    }
+    stream_args_args["block_id"] = nullid;
 
     /////////////////////////////////////////////////////////////////////////
     //////// 4. Configure blocks (packet size and rate) /////////////////////
     /////////////////////////////////////////////////////////////////////////
     std::cout << "Samples per packet coming from null source: " << spp << std::endl;
-    // To access properties, there's two ways. You can access args as defined
-    // in the XML file:
     const size_t BYTES_PER_SAMPLE = 4;
-    null_src_ctrl->set_arg<int>("bpp", int(spp * BYTES_PER_SAMPLE));
-    if (null_src_ctrl->get_arg<int>("bpp") != int(spp * BYTES_PER_SAMPLE)) {
+    null_src_ctrl->set_bytes_per_packet(uint32_t(spp * BYTES_PER_SAMPLE));
+    if (null_src_ctrl->get_bytes_per_packet() != uint32_t(spp * BYTES_PER_SAMPLE)) {
         std::cout << "[ERROR] Could not set samples per packet!" << std::endl;
         return ~0;
     }
-
-    // Or, if our block has its own getters + setters, you can call those:
-    std::cout << str(boost::format("Requesting rate:   %.2f Msps (%.2f MByte/s).")
-                     % (rate / 1e6) % (rate * 4 / 1e6))
-              << std::endl;
-    const size_t SAMPLES_PER_LINE = 2;
-    null_src_ctrl->set_line_rate(rate / SAMPLES_PER_LINE, block_rate);
-    // Now, it's possible that this requested rate is not available.
-    // Let's read back the true rate with the getter:
-    double actual_rate_mega =
-        null_src_ctrl->get_line_rate(block_rate) / 1e6 * SAMPLES_PER_LINE;
-    std::cout << str(boost::format("Actually got rate: %.2f Msps (%.2f MByte/s).")
-                     % actual_rate_mega % (actual_rate_mega * BYTES_PER_SAMPLE))
-              << std::endl;
-
-
-    /////////////////////////////////////////////////////////////////////////
-    //////// 5. Connect blocks //////////////////////////////////////////////
-    /////////////////////////////////////////////////////////////////////////
-    std::cout << "Connecting blocks..." << std::endl;
-    if (proc_block_ctrl) {
-        rx_graph->connect( // Yes, it's that easy!
-            null_src_ctrl->get_block_id(),
-            proc_block_ctrl->get_block_id());
-    }
-    if (proc_block_ctrl2 and proc_block_ctrl) {
-        rx_graph->connect(
-            proc_block_ctrl->get_block_id(), proc_block_ctrl2->get_block_id());
-    }
+    null_src_ctrl->set_throttle_cycles(throttle_cycles);
 
     /////////////////////////////////////////////////////////////////////////
-    //////// 6. Spawn receiver //////////////////////////////////////////////
+    //////// 5. Spawn receiver //////////////////////////////////////////////
     /////////////////////////////////////////////////////////////////////////
     uhd::stream_args_t stream_args(format, "sc16");
     stream_args.args        = stream_args_args;
     stream_args.args["spp"] = std::to_string(spp);
     UHD_LOGGER_DEBUG("RFNOC") << "Using streamer args: " << stream_args.args.to_string()
                               << std::endl;
-    uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
-
-#define recv_to_file_args() \
-    (rx_stream,             \
-        file,               \
-        spb,                \
-        total_num_samps,    \
-        total_time,         \
-        bw_summary,         \
-        stats,              \
+    uhd::rx_streamer::sptr rx_stream = graph->create_rx_streamer(1, stream_args);
+
+    /////////////////////////////////////////////////////////////////////////
+    //////// 6. Connect blocks //////////////////////////////////////////////
+    /////////////////////////////////////////////////////////////////////////
+    std::cout << "Connecting blocks..." << std::endl;
+    graph->connect( // Yes, it's that easy!
+        null_src_ctrl->get_block_id(),
+        0,
+        rx_stream,
+        0);
+    graph->commit();
+
+    if (total_time == 0) {
+        std::cout << "Press Ctrl + C to stop streaming..." << std::endl;
+    }
+
+#define recv_to_file_args()           \
+    (rx_stream,                       \
+        vm.count("null") ? "" : file, \
+        spb,                          \
+        total_time,                   \
+        bw_summary,                   \
+        stats,                        \
         continue_on_bad_packet)
     // recv to file
     if (format == "fc64")
diff --git a/host/examples/rfnoc_rx_to_file.cpp b/host/examples/rfnoc_rx_to_file.cpp
index 5bb9985ae..7908b2ef6 100644
--- a/host/examples/rfnoc_rx_to_file.cpp
+++ b/host/examples/rfnoc_rx_to_file.cpp
@@ -1,24 +1,16 @@
 //
 // Copyright 2014-2016 Ettus Research LLC
+// Copyright 2019 Ettus Research, a National Instruments Brand
 //
-// 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/>.
+// SPDX-License-Identifier: GPL-3.0-or-later
 //
 
-#include <uhd/device3.hpp>
 #include <uhd/exception.hpp>
-#include <uhd/rfnoc/radio_ctrl.hpp>
-#include <uhd/rfnoc/source_block_ctrl_base.hpp>
+#include <uhd/rfnoc/ddc_block_control.hpp>
+#include <uhd/rfnoc/defaults.hpp>
+#include <uhd/rfnoc/mb_controller.hpp>
+#include <uhd/rfnoc/radio_control.hpp>
+#include <uhd/rfnoc_graph.hpp>
 #include <uhd/types/sensors.hpp>
 #include <uhd/types/tune_request.hpp>
 #include <uhd/utils/safe_main.hpp>
@@ -232,9 +224,9 @@ bool check_locked_sensor(std::vector<std::string> sensor_names,
 int UHD_SAFE_MAIN(int argc, char* argv[])
 {
     // variables to be set by po
-    std::string args, file, format, ant, subdev, ref, wirefmt, streamargs, radio_args,
-        block_id, block_args;
-    size_t total_num_samps, spb, radio_id, radio_chan;
+    std::string args, file, format, ant, subdev, ref, wirefmt, streamargs, block_id,
+        block_args;
+    size_t total_num_samps, spb, spp, radio_id, radio_chan;
     double rate, freq, gain, bw, total_time, setup_time;
 
     // setup the program options
@@ -247,6 +239,7 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
         ("duration", po::value<double>(&total_time)->default_value(0), "total number of seconds to receive")
         ("nsamps", po::value<size_t>(&total_num_samps)->default_value(0), "total number of samples to receive")
         ("spb", po::value<size_t>(&spb)->default_value(10000), "samples per buffer")
+        ("spp", po::value<size_t>(&spp)->default_value(64), "samples per packet (on FPGA and wire)")
         ("streamargs", po::value<std::string>(&streamargs)->default_value(""), "stream args")
         ("progress", "periodically display short-term bandwidth")
         ("stats", "show average bandwidth on exit")
@@ -259,7 +252,6 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
 
         ("radio-id", po::value<size_t>(&radio_id)->default_value(0), "Radio ID to use (0 or 1).")
         ("radio-chan", po::value<size_t>(&radio_chan)->default_value(0), "Radio channel")
-        ("radio-args", po::value<std::string>(&radio_args), "Radio channel")
         ("rate", po::value<double>(&rate)->default_value(1e6), "RX rate of the radio block")
         ("freq", po::value<double>(&freq)->default_value(0.0), "RF center frequency in Hz")
         ("gain", po::value<double>(&gain), "gain for the RF chain")
@@ -309,24 +301,57 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
      * Create device and block controls
      ***********************************************************************/
     std::cout << std::endl;
-    std::cout << boost::format("Creating the USRP device with: %s...") % args
+    std::cout << boost::format("Creating the RFNoC graph with args: %s...") % args
               << std::endl;
-    uhd::device3::sptr usrp = uhd::device3::make(args);
+    uhd::rfnoc::rfnoc_graph::sptr graph = uhd::rfnoc::rfnoc_graph::make(args);
+
     // Create handle for radio object
     uhd::rfnoc::block_id_t radio_ctrl_id(0, "Radio", radio_id);
     // This next line will fail if the radio is not actually available
-    uhd::rfnoc::radio_ctrl::sptr radio_ctrl =
-        usrp->get_block_ctrl<uhd::rfnoc::radio_ctrl>(radio_ctrl_id);
+    uhd::rfnoc::radio_control::sptr radio_ctrl =
+        graph->get_block<uhd::rfnoc::radio_control>(radio_ctrl_id);
     std::cout << "Using radio " << radio_id << ", channel " << radio_chan << std::endl;
 
+    // Enumerate blocks in the chain
+    auto edges = graph->enumerate_static_connections();
+
+    std::string source_block = radio_ctrl->get_block_id();
+    size_t source_port       = radio_chan;
+    auto chain               = std::vector<uhd::rfnoc::graph_edge_t>();
+    uhd::rfnoc::ddc_block_control::sptr ddc_ctrl;
+    size_t ddc_chan = 0;
+    while (true) {
+        std::cout << "Looking for source block " << source_block << ", port "
+                  << source_port << std::endl;
+        bool src_found = false;
+        for (auto& edge : edges) {
+            if (edge.src_blockid == source_block && edge.src_port == source_port) {
+                auto blockid = uhd::rfnoc::block_id_t(source_block);
+                if (blockid.match("DDC")) {
+                    ddc_ctrl = graph->get_block<uhd::rfnoc::ddc_block_control>(blockid);
+                    ddc_chan = edge.src_port;
+                }
+                src_found = true;
+                chain.push_back(edge);
+                source_block = edge.dst_blockid;
+                source_port  = edge.dst_port;
+            }
+        }
+        if (not src_found) {
+            std::cerr << "ERROR: Failed to find target source block" << std::endl;
+            break;
+        }
+        if (uhd::rfnoc::block_id_t(source_block).match(uhd::rfnoc::NODE_ID_SEP)) {
+            break;
+        }
+    }
+
     /************************************************************************
      * Set up radio
      ***********************************************************************/
-    radio_ctrl->set_args(radio_args);
-
     // Lock mboard clocks
     if (vm.count("ref")) {
-        radio_ctrl->set_clock_source(ref);
+        graph->get_mb_controller(0)->set_clock_source(ref);
     }
 
     // set the sample rate
@@ -335,10 +360,19 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
         return EXIT_FAILURE;
     }
     std::cout << boost::format("Setting RX Rate: %f Msps...") % (rate / 1e6) << std::endl;
-    radio_ctrl->set_rate(rate);
-    std::cout << boost::format("Actual RX Rate: %f Msps...")
-                     % (radio_ctrl->get_rate() / 1e6)
-              << std::endl
+    double radio_rate = radio_ctrl->get_rate();
+    if (ddc_ctrl) {
+        std::cout << "DDC block found" << std::endl;
+        int decim = (int)(radio_rate / rate);
+        std::cout << boost::format("Setting decimation value to %d") % decim << std::endl;
+        ddc_ctrl->set_property<int>("decim", decim, ddc_chan);
+        decim = ddc_ctrl->get_property<int>("decim", ddc_chan);
+        std::cout << boost::format("Actual decimation value is %d") % decim << std::endl;
+        rate = radio_rate / decim;
+    } else {
+        rate = radio_ctrl->set_rate(rate);
+    }
+    std::cout << boost::format("Actual RX Rate: %f Msps...") % (rate / 1e6) << std::endl
               << std::endl;
 
     // set the center frequency
@@ -392,53 +426,68 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
         // setup_time);
     }
 
-    size_t spp = radio_ctrl->get_arg<int>("spp");
+    std::cout << "Setting samples per packet to: " << spp << std::endl;
+    radio_ctrl->set_property<int>("spp", spp, 0);
+    spp = radio_ctrl->get_property<int>("spp", 0);
+    std::cout << "Actual samples per packet = " << spp << std::endl;
 
     /************************************************************************
      * Set up streaming
      ***********************************************************************/
     uhd::device_addr_t streamer_args(streamargs);
 
-    uhd::rfnoc::graph::sptr rx_graph = usrp->create_graph("rfnoc_rx_to_file");
-    usrp->clear();
-    // Set the stream args on the radio:
-    if (block_id.empty()) {
-        // If no extra block is required, connect to the radio:
-        streamer_args["block_id"]   = radio_ctrl_id.to_string();
-        streamer_args["block_port"] = str(boost::format("%d") % radio_chan);
-    } else {
-        // Otherwise, see if the requested block exists and connect it to the radio:
-        if (not usrp->has_block(block_id)) {
-            std::cout << "Block does not exist on current device: " << block_id
-                      << std::endl;
-            return EXIT_FAILURE;
-        }
-
-        uhd::rfnoc::source_block_ctrl_base::sptr blk_ctrl =
-            usrp->get_block_ctrl<uhd::rfnoc::source_block_ctrl_base>(block_id);
-
-        if (not block_args.empty()) {
-            // Set the block args on the other block:
-            blk_ctrl->set_args(uhd::device_addr_t(block_args));
-        }
-        // Connect:
-        std::cout << "Connecting " << radio_ctrl_id << " ==> " << blk_ctrl->get_block_id()
-                  << std::endl;
-        rx_graph->connect(
-            radio_ctrl_id, radio_chan, blk_ctrl->get_block_id(), uhd::rfnoc::ANY_PORT);
-        streamer_args["block_id"] = blk_ctrl->get_block_id().to_string();
-
-        spp = blk_ctrl->get_args().cast<size_t>("spp", spp);
-    }
-
     // create a receive streamer
-    std::cout << "Samples per packet: " << spp << std::endl;
+    // std::cout << "Samples per packet: " << spp << std::endl;
     uhd::stream_args_t stream_args(
         format, "sc16"); // We should read the wire format from the blocks
-    stream_args.args        = streamer_args;
-    stream_args.args["spp"] = boost::lexical_cast<std::string>(spp);
+    stream_args.args = streamer_args;
+    // TODO?
+    // stream_args.args["spp"] = boost::lexical_cast<std::string>(spp);
     std::cout << "Using streamer args: " << stream_args.args.to_string() << std::endl;
-    uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
+    uhd::rx_streamer::sptr rx_stream = graph->create_rx_streamer(1, stream_args);
+
+    // Set the stream args on the radio:
+    // if (block_id.empty()) {
+    //    // If no extra block is required, connect to the radio:
+    //    streamer_args["block_id"]   = radio_ctrl_id.to_string();
+    //    streamer_args["block_port"] = str(boost::format("%d") % radio_chan);
+    //} else {
+    //    // Otherwise, see if the requested block exists and connect it to the radio:
+    //    if (not usrp->has_block(block_id)) {
+    //        std::cout << "Block does not exist on current device: " << block_id
+    //                  << std::endl;
+    //        return EXIT_FAILURE;
+    //    }
+
+    //    uhd::rfnoc::source_block_ctrl_base::sptr blk_ctrl =
+    //        usrp->get_block_ctrl<uhd::rfnoc::source_block_ctrl_base>(block_id);
+
+    //    if (not block_args.empty()) {
+    //        // Set the block args on the other block:
+    //        blk_ctrl->set_args(uhd::device_addr_t(block_args));
+    //    }
+    //    // Connect:
+    //    std::cout << "Connecting " << radio_ctrl_id << " ==> " <<
+    //    blk_ctrl->get_block_id()
+    //              << std::endl;
+    //    rx_graph->connect(
+    //        radio_ctrl_id, radio_chan, blk_ctrl->get_block_id(), uhd::rfnoc::ANY_PORT);
+    //    streamer_args["block_id"] = blk_ctrl->get_block_id().to_string();
+
+    //    spp = blk_ctrl->get_args().cast<size_t>("spp", spp);
+    //}
+
+    // Connect blocks and commit the graph
+    for (auto& edge : chain) {
+        if (uhd::rfnoc::block_id_t(edge.dst_blockid).match(uhd::rfnoc::NODE_ID_SEP)) {
+            graph->connect(edge.src_blockid, edge.src_port, rx_stream, 0);
+        } else {
+            graph->connect(
+                edge.src_blockid, edge.src_port, edge.dst_blockid, edge.dst_port);
+        }
+    }
+    graph->commit();
+
 
     if (total_num_samps == 0) {
         std::signal(SIGINT, &sig_int_handler);
diff --git a/host/examples/test_messages.cpp b/host/examples/test_messages.cpp
index 0d0e958b8..fe2293840 100644
--- a/host/examples/test_messages.cpp
+++ b/host/examples/test_messages.cpp
@@ -1,6 +1,7 @@
 //
 // Copyright 2010-2013 Ettus Research LLC
 // Copyright 2018 Ettus Research, a National Instruments Company
+// Copyright 2019 Ettus Research, a National Instruments Brand
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
@@ -48,14 +49,14 @@ bool test_late_command_message(uhd::usrp::multi_usrp::sptr usrp,
 
     switch (md.error_code) {
         case uhd::rx_metadata_t::ERROR_CODE_LATE_COMMAND:
-            std::cout << boost::format("success:\n"
-                                       "    Got error code late command message.\n")
+            std::cout << "success:\n"
+                      << "    Got error code late command message.\n"
                       << std::endl;
             return true;
 
         case uhd::rx_metadata_t::ERROR_CODE_TIMEOUT:
-            std::cout << boost::format("failed:\n"
-                                       "    Inline message recv timed out.\n")
+            std::cout << "failed:\n"
+                      << "    Inline message recv timed out.\n"
                       << std::endl;
             return false;
 
@@ -141,16 +142,16 @@ bool test_burst_ack_message(
 
     uhd::async_metadata_t async_md;
     if (not tx_stream->recv_async_msg(async_md)) {
-        std::cout << boost::format("failed:\n"
-                                   "    Async message recv timed out.\n")
+        std::cout << "failed:\n"
+                  << "    Async message recv timed out.\n"
                   << std::endl;
         return false;
     }
 
     switch (async_md.event_code) {
         case uhd::async_metadata_t::EVENT_CODE_BURST_ACK:
-            std::cout << boost::format("success:\n"
-                                       "    Got event code burst ack message.\n")
+            std::cout << "success:\n"
+                      << "    Got event code burst ack message.\n"
                       << std::endl;
             return true;
 
@@ -182,27 +183,35 @@ bool test_underflow_message(
     tx_stream->send(&buff.front(), buff.size(), md);
 
     uhd::async_metadata_t async_md;
+    bool result = false;
     if (not tx_stream->recv_async_msg(async_md, 1)) {
         std::cout << boost::format("failed:\n"
                                    "    Async message recv timed out.\n")
                   << std::endl;
-        return false;
+    } else {
+        switch (async_md.event_code) {
+            case uhd::async_metadata_t::EVENT_CODE_UNDERFLOW:
+                std::cout << boost::format("success:\n"
+                                           "    Got event code underflow message.\n")
+                          << std::endl;
+                result = true;
+                break;
+
+            default:
+                std::cout << boost::format("failed:\n"
+                                           "    Got unexpected event code 0x%x.\n")
+                                 % async_md.event_code
+                          << std::endl;
+                break;
+        }
     }
 
-    switch (async_md.event_code) {
-        case uhd::async_metadata_t::EVENT_CODE_UNDERFLOW:
-            std::cout << boost::format("success:\n"
-                                       "    Got event code underflow message.\n")
-                      << std::endl;
-            return true;
-
-        default:
-            std::cout << boost::format("failed:\n"
-                                       "    Got unexpected event code 0x%x.\n")
-                             % async_md.event_code
-                      << std::endl;
-            return false;
-    }
+    // Finish the burst to avoid affecting other tests. The DUC only considers
+    // time specs from the beginning of a burst, if other tests need a time
+    // spec they would be affected by an unfinished burst.
+    md.end_of_burst = true;
+    tx_stream->send(&buff.front(), buff.size(), md);
+    return result;
 }
 
 /*!
@@ -314,12 +323,15 @@ int UHD_SAFE_MAIN(int argc, char* argv[])
     //------------------------------------------------------------------
     // begin messages test
     //------------------------------------------------------------------
-    static uhd::dict<std::string,
-        boost::function<bool(
-            uhd::usrp::multi_usrp::sptr, uhd::rx_streamer::sptr, uhd::tx_streamer::sptr)>>
-        tests = boost::assign::map_list_of("Test Burst ACK ", &test_burst_ack_message)(
-            "Test Underflow ", &test_underflow_message)("Test Time Error",
-            &test_time_error_message)("Test Late Command", &test_late_command_message);
+    using test_executor_fn = std::function<bool(
+        uhd::usrp::multi_usrp::sptr, uhd::rx_streamer::sptr, uhd::tx_streamer::sptr)>;
+    // clang-format off
+    uhd::dict<std::string, test_executor_fn> tests = boost::assign::map_list_of
+        ("Test Burst ACK ", &test_burst_ack_message)
+        ("Test Underflow ", &test_underflow_message)
+        ("Test Time Error", &test_time_error_message)
+        ("Test Late Command", &test_late_command_message);
+    // clang-format on
 
     if (vm.count("test-chain")) {
         tests["Test Broken Chain"] = &test_broken_chain_message;