gras: enable half consumed metric on pool buffers

3 files changed, 27 insertions, 3 deletions

diff --git a/lib/block_allocator.cpp b/lib/block_allocator.cpp
index bd2f3c2..fb00d58 100644
--- a/lib/block_allocator.cpp
+++ b/lib/block_allocator.cpp
@@ -9,13 +9,14 @@ using namespace gras;
 
 const size_t AT_LEAST_BYTES = 32*(1024); //kiB per buffer
 const size_t AHH_TOO_MANY_BYTES = 32*(1024*1024); //MiB enough for me
-const size_t THIS_MANY_BUFFERS = 8; //pool size
+const size_t THIS_MANY_BUFFERS = 2; //pool size
 
 static void buffer_returner(ThreadPool tp, Theron::Address addr, const size_t index, SBuffer &buffer)
 {
     //reset offset and length
     buffer.offset = 0;
     buffer.length = 0;
+    buffer.last = NULL;
 
     OutputBufferMessage message;
     message.index = index;
diff --git a/lib/buffer_queue_pool.cpp b/lib/buffer_queue_pool.cpp
index 0b2d343..79e2cc3 100644
--- a/lib/buffer_queue_pool.cpp
+++ b/lib/buffer_queue_pool.cpp
@@ -31,8 +31,21 @@ struct BufferQueuePool : BufferQueue
     void pop(void)
     {
         ASSERT(not _queue.empty());
-        _queue.front().reset(); //dont hold ref
-        _queue.pop_front();
+        SBuffer &buff = _queue.front();
+
+        //This little half consumed metric lets us keep using
+        //the same buffer if its only been partially consumed.
+        //Input buffer stitching will rejoin contiguous memory.
+        if (buff.offset > buff.get_actual_length()/2)
+        {
+            buff.reset(); //dont hold ref
+            _queue.pop_front();
+        }
+        else
+        {
+            //enables buffer stitching on pool buffers
+            buff.last = buff.get();
+        }
     }
 
     void push(const SBuffer &buff)
diff --git a/lib/gras_impl/input_buffer_queues.hpp b/lib/gras_impl/input_buffer_queues.hpp
index 7bdbddc..e45bc06 100644
--- a/lib/gras_impl/input_buffer_queues.hpp
+++ b/lib/gras_impl/input_buffer_queues.hpp
@@ -282,6 +282,7 @@ GRAS_FORCE_INLINE void InputBufferQueues::push(const size_t i, const SBuffer &bu
     __update(i);
 
     #ifdef GRAS_ENABLE_BUFFER_STITCHING
+    if (_queues[i].size() <= 1) return;
     //stitch:
     for (size_t j = _queues[i].size()-1; j > 0; j--)
     {
@@ -298,6 +299,15 @@ GRAS_FORCE_INLINE void InputBufferQueues::push(const size_t i, const SBuffer &bu
             b1.last = b0.get(b0.length);
         }
     }
+
+    //back got fully stitched and it was the same buffer -> pop it
+    SBuffer &b1 = _queues[i].back();
+    SBuffer &b0 = _queues[i][_queues[i].size()-2];
+    if (b1 == b0 and b1.length == 0)
+    {
+        b1.reset();
+        _queues[i].pop_back();
+    }
     #endif //GRAS_ENABLE_BUFFER_STITCHING
 
 }