From e3f85ddc8ea565bc81b538269298a9f97b055c8c Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Sun, 23 Mar 2014 14:10:45 +0100
Subject: Fix livelock in synchronous ZeroMQ scenario

---
 src/InputZeroMQReader.cpp | 11 ++++++++---
 src/OutputUHD.cpp         |  2 ++
 src/ThreadsafeQueue.h     | 11 ++++++++---
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/InputZeroMQReader.cpp b/src/InputZeroMQReader.cpp
index afb6b7d..483429b 100644
--- a/src/InputZeroMQReader.cpp
+++ b/src/InputZeroMQReader.cpp
@@ -3,7 +3,7 @@
    Her Majesty the Queen in Right of Canada (Communications Research
    Center Canada)
 
-   Copyrigth (C) 2013
+   Copyrigth (C) 2013, 2014
    Matthias P. Braendli, matthias.braendli@mpb.li
  */
 /*
@@ -117,12 +117,15 @@ void InputZeroMQWorker::RecvProcess(struct InputZeroMQThreadData* workerdata)
             }
             else
             {
+                workerdata->in_messages->notify();
+
                 if (!buffer_full) {
-                    workerdata->in_messages->notify();
                     fprintf(stderr, "ZeroMQ buffer overfull !\n");
 
                     buffer_full = true;
                 }
+
+                queue_size = workerdata->in_messages->size();
             }
 
             if (queue_size < 5) {
@@ -132,9 +135,11 @@ void InputZeroMQWorker::RecvProcess(struct InputZeroMQThreadData* workerdata)
         }
     }
     catch (zmq::error_t& err) {
-        printf("ZeroMQ error in RecvProcess: '%s'\n", err.what());
+        fprintf(stderr, "ZeroMQ error in RecvProcess: '%s'\n", err.what());
     }
 
+    fprintf(stderr, "ZeroMQ input worker terminated\n");
+
     subscriber.close();
 }
 
diff --git a/src/OutputUHD.cpp b/src/OutputUHD.cpp
index bd4231e..73bd38e 100644
--- a/src/OutputUHD.cpp
+++ b/src/OutputUHD.cpp
@@ -590,6 +590,8 @@ loopend:
         // swap buffers
         workerbuffer = (workerbuffer + 1) % 2;
     }
+
+    uwd->logger->level(warn) << "UHD worker terminated";
 }
 
 
diff --git a/src/ThreadsafeQueue.h b/src/ThreadsafeQueue.h
index 3dd5450..78e9ef0 100644
--- a/src/ThreadsafeQueue.h
+++ b/src/ThreadsafeQueue.h
@@ -54,7 +54,8 @@ public:
     /* Create a queue where it has to contain at least
      * required_size elements before pop is possible
      */
-    ThreadsafeQueue(size_t required_size) : the_required_size(required_size) {}
+    ThreadsafeQueue(size_t required_size) : the_required_size(required_size) {
+    }
 
     /* Push one element into the queue, and notify another thread that
      * might be waiting.
@@ -84,6 +85,11 @@ public:
         return the_queue.empty();
     }
 
+    size_t size() const
+    {
+        return the_queue.size();
+    }
+
     bool try_pop(T& popped_value)
     {
         boost::mutex::scoped_lock lock(the_mutex);
@@ -100,8 +106,7 @@ public:
     void wait_and_pop(T& popped_value)
     {
         boost::mutex::scoped_lock lock(the_mutex);
-        while(the_queue.size() < the_required_size)
-        {
+        while(the_queue.size() < the_required_size) {
             the_condition_variable.wait(lock);
         }
 
-- 
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