Optimize cell-ewma circuit priority algorithm.

There are two big changes here:
  - We store active circuits in a priority queue for each or_conn,
    rather than doing a linear search over all the active circuits
    before we send each cell.
  - Rather than multiplying every circuit's cell-ewma by a decay
    factor every time we send a cell (thus normalizing the value of a
    current cell to 1.0 and a past cell to alpha^t), we instead
    only scale down the cell-ewma every tick (ten seconds atm),
    normalizing so that a cell sent at the start of the tick has
    value 1.0).

1 files changed, 8 insertions, 4 deletions

diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index eb8c90f460..0dff873cf6 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -386,8 +386,10 @@ init_circuit_base(circuit_t *circ)
   circ->deliver_window = CIRCWINDOW_START;
 
   /* Initialize the cell_ewma_t structure */
-  circ->n_cell_ewma.last_cell_time = circ->highres_created;
+  circ->n_cell_ewma.last_adjusted_tick = cell_ewma_get_tick();
   circ->n_cell_ewma.cell_count = 0.0;
+  circ->n_cell_ewma.heap_index = -1;
+  circ->n_cell_ewma.is_for_p_conn = 0;
 
   circuit_add(circ);
 }
@@ -438,11 +440,13 @@ or_circuit_new(circid_t p_circ_id, or_connection_t *p_conn)
 
   /* Initialize the cell_ewma_t structure */
 
-  /* Fetch the timeval that init_circuit_base filled in. */
-  circ->p_cell_ewma.last_cell_time = TO_CIRCUIT(circ)->highres_created;
-
   /* Initialize the cell counts to 0 */
   circ->p_cell_ewma.cell_count = 0.0;
+  circ->p_cell_ewma.last_adjusted_tick = cell_ewma_get_tick();
+  circ->p_cell_ewma.is_for_p_conn = 1;
+
+  /* It's not in any heap yet. */
+  circ->p_cell_ewma.heap_index = -1;
 
   return circ;
 }