Favor quiet circuits when choosing which order to relay cells in.

Each circuit is ranked in terms of how many cells from it have been
relayed recently, using a time-weighted average.

This patch has been tested this on a private Tor network on PlanetLab,
and gotten improvements of 12-35% in time it takes to fetch a small
web page while there's a simultaneous large data transfer going on
simultaneously.

[Commit msg by nickm based on mail from Ian Goldberg.]

1 files changed, 24 insertions, 4 deletions

diff --git a/src/or/connection.c b/src/or/connection.c
index 0ff1cc5876..bd12e36180 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -2275,8 +2275,8 @@ connection_read_bucket_should_increase(or_connection_t *conn)
  * Mark the connection and return -1 if you want to close it, else
  * return 0.
  */
-int
-connection_handle_read(connection_t *conn)
+static int
+connection_handle_read_impl(connection_t *conn)
 {
   int max_to_read=-1, try_to_read;
   size_t before, n_read = 0;
@@ -2371,6 +2371,17 @@ loop_again:
   return 0;
 }
 
+int
+connection_handle_read(connection_t *conn)
+{
+  int res;
+
+  tor_gettimeofday_cache_clear();
+  res = connection_handle_read_impl(conn);
+  return res;
+  
+}
+
 /** Pull in new bytes from conn-\>s or conn-\>linked_conn onto conn-\>inbuf,
  * either directly or via TLS. Reduce the token buckets by the number of bytes
  * read.
@@ -2572,8 +2583,8 @@ connection_outbuf_too_full(connection_t *conn)
  * Mark the connection and return -1 if you want to close it, else
  * return 0.
  */
-int
-connection_handle_write(connection_t *conn, int force)
+static int
+connection_handle_write_impl(connection_t *conn, int force)
 {
   int e;
   socklen_t len=(socklen_t)sizeof(e);
@@ -2740,6 +2751,15 @@ connection_handle_write(connection_t *conn, int force)
   return 0;
 }
 
+int
+connection_handle_write(connection_t *conn, int force)
+{
+    int res;
+    tor_gettimeofday_cache_clear();
+    res = connection_handle_write_impl(conn, force);
+    return res;
+}
+
 /** OpenSSL TLS record size is 16383; this is close. The goal here is to
  * push data out as soon as we know there's enough for a TLS record, so
  * during periods of high load we won't read entire megabytes from