Add a new notion of "stamps" to be a fast 32-bit monotonic timestamp

The goal here is to replace our use of msec-based timestamps with
something less precise, but easier to calculate.  We're doing this
because calculating lots of msec-based timestamps requires lots of
64/32 division operations, which can be inefficient on 32-bit
platforms.

We make sure that these stamps can be calculated using only the
coarse monotonic timer and 32-bit bitwise operations.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/or/or.h b/src/or/or.h
index 809714b5e2..59cceb72ce 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -1166,8 +1166,8 @@ typedef struct packed_cell_t {
   /** Next cell queued on this circuit. */
   TOR_SIMPLEQ_ENTRY(packed_cell_t) next;
   char body[CELL_MAX_NETWORK_SIZE]; /**< Cell as packed for network. */
-  uint32_t inserted_time; /**< Time (in milliseconds since epoch, with high
-                           * bits truncated) when this cell was inserted. */
+  uint32_t inserted_timestamp; /**< Time (in timestamp units) when this cell
+                                * was inserted */
 } packed_cell_t;
 
 /** A queue of cells on a circuit, waiting to be added to the