[Boost-commit] svn:boost r66158 - trunk/boost/asio/detail

Subject: [Boost-commit] svn:boost r66158 - trunk/boost/asio/detail
From: chris_at_[hidden]
Date: 2010-10-23 22:06:52

Author: chris_kohlhoff
Date: 2010-10-23 22:06:46 EDT (Sat, 23 Oct 2010)
New Revision: 66158
URL: http://svn.boost.org/trac/boost/changeset/66158

Log:
Fix vector reallocation performance problem. Refs #4780.

Text files modified: 
   trunk/boost/asio/detail/timer_queue.hpp |    31 ++++++++++++++++---------------         
   1 files changed, 16 insertions(+), 15 deletions(-)

Modified: trunk/boost/asio/detail/timer_queue.hpp
==============================================================================
--- trunk/boost/asio/detail/timer_queue.hpp	(original)
+++ trunk/boost/asio/detail/timer_queue.hpp	2010-10-23 22:06:46 EDT (Sat, 23 Oct 2010)
@@ -79,36 +79,37 @@
   // function call may need to be interrupted and restarted.
   bool enqueue_timer(const time_type& time, per_timer_data& timer, timer_op* op)
   {
-    // Ensure that there is space for the timer in the heap. We reserve here so
-    // that the push_back below will not throw due to a reallocation failure.
-    heap_.reserve(heap_.size() + 1);
-
-    timer.op_queue_.push(op);
+    // Enqueue the timer object.
     if (timer.prev_ == 0 && &timer != timers_)
     {
-      // Insert the new timer into the linked list of active timers.
-      timer.next_ = timers_;
-      timer.prev_ = 0;
-      if (timers_)
-        timers_->prev_ = &timer;
-      timers_ = &timer;
-
-      // Put the new timer at the correct position in the heap.
       if (this->is_positive_infinity(time))
       {
+        // No heap entry is required for timers that never expire.
         timer.heap_index_ = (std::numeric_limits<std::size_t>::max)();
-        return false; // No need to interrupt reactor as timer never expires.
       }
       else
       {
+        // Put the new timer at the correct position in the heap. This is done
+        // first since push_back() can throw due to allocation failure.
         timer.heap_index_ = heap_.size();
         heap_entry entry = { time, &timer };
         heap_.push_back(entry);
         up_heap(heap_.size() - 1);
       }
+
+      // Insert the new timer into the linked list of active timers.
+      timer.next_ = timers_;
+      timer.prev_ = 0;
+      if (timers_)
+        timers_->prev_ = &timer;
+      timers_ = &timer;
     }
 
-    return (heap_[0].timer_ == &timer);
+    // Enqueue the individual timer operation.
+    timer.op_queue_.push(op);
+
+    // Interrupt reactor only if newly added timer is first to expire.
+    return timer.heap_index_ == 0 && timer.op_queue_.front() == op;
   }
 
   // Whether there are no timers in the queue.