QPID-3960: Fix performance regression in priority queue implementation.

Revision r1307582 created a serious degredation in priority queue performance.

It replaced a muti-deque implementation with o(1) complexity for consuming with
a map implementation with o(log(n)) performance.

This revision returns to a mutli-deque algorithm but with the addition
of a FIFO index for fast browsing of acquired and unacquired messages.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1329301 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 11 insertions, 8 deletions

diff --git a/qpid/cpp/src/qpid/broker/Fairshare.h b/qpid/cpp/src/qpid/broker/Fairshare.h
index dfcbdf280e..1b25721e0c 100644
--- a/qpid/cpp/src/qpid/broker/Fairshare.h
+++ b/qpid/cpp/src/qpid/broker/Fairshare.h
@@ -22,7 +22,6 @@
  *
  */
 #include "qpid/broker/PriorityQueue.h"
-#include <vector>
 
 namespace qpid {
 namespace framing {
@@ -39,19 +38,23 @@ class Fairshare : public PriorityQueue
 {
   public:
     Fairshare(size_t levels, uint limit);
-    bool getState(qpid::framing::FieldTable& counts) const;
-    bool setState(const qpid::framing::FieldTable& counts);
+    bool getState(uint& priority, uint& count) const;
+    bool setState(uint priority, uint count);
     void setLimit(size_t level, uint limit);
     bool isNull();
-    bool consume(QueuedMessage&);
     static std::auto_ptr<Messages> create(const qpid::framing::FieldTable& settings);
-    static bool getState(const Messages&, qpid::framing::FieldTable& counts);
-    static bool setState(Messages&, const qpid::framing::FieldTable& counts);
+    static bool getState(const Messages&, uint& priority, uint& count);
+    static bool setState(Messages&, uint priority, uint count);
   private:
     std::vector<uint> limits;
-    std::vector<uint> counts;
 
-    bool checkLevel(uint level);
+    uint priority;
+    uint count;
+
+    uint currentLevel();
+    uint nextLevel();
+    bool limitReached();
+    bool findFrontLevel(uint& p, PriorityLevels&);
 };
 }} // namespace qpid::broker