changed lookahead to preload, thats all it is

8 files changed, 22 insertions, 28 deletions

diff --git a/gnuradio b/gnuradio
-Subproject 6c619cf23423d771289a34dbe8aa8937a42fca8
+Subproject ead17717d94cd40b153a8748bf5a1f94b13969c
diff --git a/include/gras/block.hpp b/include/gras/block.hpp
index 68bd051..71da047 100644
--- a/include/gras/block.hpp
+++ b/include/gras/block.hpp
@@ -58,15 +58,19 @@ struct GRAS_API InputPortConfig
     bool inline_buffer;
 
     /*!
-     * Set the number of input buffer look-ahead items.
-     * When num look-ahead items are not consumed,
-     * they will be available for the next work call.
-     * This is used to implement sample memory for
+     * Preload the input queue with num preload items.
+     * All items preloaded into the buffer will be 0.
+     * This is used to implement zero-padding for
      * things like sliding dot products/FIR filters.
      *
+     *  - Increasing the preload at runtime will
+     * inject more items into the input queue.
+     *  - Decreasing the preload at runtime will
+     * consume random items from the input queue.
+     *
      * Default = 0.
      */
-    size_t lookahead_items;
+    size_t preload_items;
 };
 
 //! Configuration parameters for an output port
diff --git a/lib/block.cpp b/lib/block.cpp
index 945b1e9..878bd16 100644
--- a/lib/block.cpp
+++ b/lib/block.cpp
@@ -11,7 +11,7 @@ InputPortConfig::InputPortConfig(void)
     reserve_items = 1;
     maximum_items = 0;
     inline_buffer = false;
-    lookahead_items = 0;
+    preload_items = 0;
 }
 
 OutputPortConfig::OutputPortConfig(void)
diff --git a/lib/block_allocator.cpp b/lib/block_allocator.cpp
index 72d8150..64b3aed 100644
--- a/lib/block_allocator.cpp
+++ b/lib/block_allocator.cpp
@@ -10,7 +10,6 @@ using namespace gras;
 const size_t AT_LEAST_DEFAULT_ITEMS = 1 << 13;
 const size_t AHH_TOO_MANY_BYTES = 1 << 20; //TODO
 const size_t THIS_MANY_BUFFERS = 32;
-const double EDGE_CASE_MITIGATION = 8.0; //edge case mitigation constant
 
 //TODO will need more complicated later
 
@@ -39,15 +38,8 @@ static size_t recommend_length(
         min_bytes = std::max(min_bytes, hint.reserve_bytes);
     }
 
-    //step 2) N x super reserve to minimize history edge case
+    //step 2) N x super reserve of hard-coded mimimum items
     size_t Nmin_bytes = min_bytes;
-    BOOST_FOREACH(const OutputHintMessage &hint, hints)
-    {
-        while (hint.history_bytes*EDGE_CASE_MITIGATION > Nmin_bytes)
-        {
-            Nmin_bytes += min_bytes;
-        }
-    }
     while (hint_bytes > Nmin_bytes)
     {
         Nmin_bytes += min_bytes;
diff --git a/lib/block_handlers.cpp b/lib/block_handlers.cpp
index 3d66ec9..3eb39db 100644
--- a/lib/block_handlers.cpp
+++ b/lib/block_handlers.cpp
@@ -54,7 +54,6 @@ void BlockActor::handle_top_token(
         //TODO, schedule this message as a pre-allocation message
         //tell the upstream about the input requirements
         OutputHintMessage output_hints;
-        output_hints.history_bytes = this->input_configs[i].lookahead_items*this->input_items_sizes[i];
         output_hints.reserve_bytes = this->input_configs[i].reserve_items*this->input_items_sizes[i];
         output_hints.token = this->input_tokens[i];
         this->post_upstream(i, output_hints);
diff --git a/lib/gras_impl/input_buffer_queues.hpp b/lib/gras_impl/input_buffer_queues.hpp
index a6b6ff8..e8b994b 100644
--- a/lib/gras_impl/input_buffer_queues.hpp
+++ b/lib/gras_impl/input_buffer_queues.hpp
@@ -169,7 +169,7 @@ struct InputBufferQueues
     std::vector<size_t> _reserve_bytes;
     std::vector<size_t> _maximum_bytes;
     std::vector<boost::circular_buffer<SBuffer> > _queues;
-    std::vector<size_t> _history_bytes;
+    std::vector<size_t> _preload_bytes;
     std::vector<boost::shared_ptr<BufferQueue> > _aux_queues;
 };
 
@@ -182,7 +182,7 @@ GRAS_FORCE_INLINE void InputBufferQueues::resize(const size_t size)
     _reserve_bytes.resize(size, 1);
     _maximum_bytes.resize(size, MAX_AUX_BUFF_BYTES);
     _queues.resize(size, boost::circular_buffer<SBuffer>(MAX_QUEUE_SIZE));
-    _history_bytes.resize(size, 0);
+    _preload_bytes.resize(size, 0);
     _aux_queues.resize(size);
 
 }
@@ -190,7 +190,7 @@ GRAS_FORCE_INLINE void InputBufferQueues::resize(const size_t size)
 inline void InputBufferQueues::update_config(
     const size_t i,
     const size_t item_size,
-    const size_t hist_bytes,
+    const size_t preload_bytes,
     const size_t reserve_bytes,
     const size_t maximum_bytes
 )
@@ -211,28 +211,28 @@ inline void InputBufferQueues::update_config(
         _aux_queues[i]->allocate_one(_maximum_bytes[i]);
     }
 
-    //there is history, so enqueue some initial history
-    if (hist_bytes > _history_bytes[i])
+    //there is preload, so enqueue some initial preload
+    if (preload_bytes > _preload_bytes[i])
     {
         SBuffer buff = _aux_queues[i]->front();
         _aux_queues[i]->pop();
 
-        const size_t delta = hist_bytes - _history_bytes[i];
+        const size_t delta = preload_bytes - _preload_bytes[i];
         std::memset(buff.get_actual_memory(), 0, delta);
         buff.offset = 0;
         buff.length = delta;
 
         this->push(i, buff);
     }
-    if (hist_bytes < _history_bytes[i])
+    if (preload_bytes < _preload_bytes[i])
     {
-        size_t delta = _history_bytes[i] - hist_bytes;
+        size_t delta = _preload_bytes[i] - preload_bytes;
         delta = std::min(delta, _enqueued_bytes[i]); //FIXME
         //TODO consume extra delta on push...? so we dont need std::min
         this->consume(i, delta);
     }
 
-    _history_bytes[i] = hist_bytes;
+    _preload_bytes[i] = preload_bytes;
     _reserve_bytes[i] = reserve_bytes;
     this->__update(i);
 }
diff --git a/lib/gras_impl/messages.hpp b/lib/gras_impl/messages.hpp
index bc6a2b8..eae3258 100644
--- a/lib/gras_impl/messages.hpp
+++ b/lib/gras_impl/messages.hpp
@@ -97,7 +97,6 @@ struct OutputCheckMessage
 struct OutputHintMessage
 {
     size_t index;
-    size_t history_bytes;
     size_t reserve_bytes;
     WeakToken token;
 };
diff --git a/lib/topology_handler.cpp b/lib/topology_handler.cpp
index f434377..cf757d5 100644
--- a/lib/topology_handler.cpp
+++ b/lib/topology_handler.cpp
@@ -95,9 +95,9 @@ void BlockActor::handle_update_inputs(
 
     for (size_t i = 0; i < num_inputs; i++)
     {
-        const size_t hist_bytes = this->input_items_sizes[i]*this->input_configs[i].lookahead_items;
+        const size_t preload_bytes = this->input_items_sizes[i]*this->input_configs[i].preload_items;
         const size_t reserve_bytes = this->input_items_sizes[i]*this->input_configs[i].reserve_items;
         const size_t maximum_bytes = this->input_items_sizes[i]*this->input_configs[i].maximum_items;
-        this->input_queues.update_config(i, this->input_items_sizes[i], hist_bytes, reserve_bytes, maximum_bytes);
+        this->input_queues.update_config(i, this->input_items_sizes[i], preload_bytes, reserve_bytes, maximum_bytes);
     }
 }