score: Fix performance issue for 64-bit timestamps

The 64-bit timestamps were introduced to simplify the timestamp
calculations.  This works well since nearly all operations are
additions.  The previous _TOD_Tickle_ticks() implementation had a
serious performance regression in case of 64-bit timestamps due to the
usage of two 64-bit divisions which are quite expensive on some
architectures.

A new field seconds_trigger in TOD_Control is introduced to trigger the
_Watchdog_Tickle_seconds() in _TOD_Tickle_ticks().  This avoids the
64-bit divisions completely and only 32-bit additions are used.

1 files changed, 2 insertions, 0 deletions

diff --git a/cpukit/score/src/coretodset.c b/cpukit/score/src/coretodset.c
index 9708ef9477..8b0928af60 100644
--- a/cpukit/score/src/coretodset.c
+++ b/cpukit/score/src/coretodset.c
@@ -25,6 +25,7 @@ void _TOD_Set_with_timestamp(
   const Timestamp_Control *tod
 )
 {
+  uint32_t nanoseconds = _Timestamp_Get_nanoseconds( tod );
   Watchdog_Interval seconds_next = _Timestamp_Get_seconds( tod );
   Watchdog_Interval seconds_now;
 
@@ -39,6 +40,7 @@ void _TOD_Set_with_timestamp(
     _Watchdog_Adjust_seconds( WATCHDOG_FORWARD, seconds_next - seconds_now );
 
   _TOD.now = *tod;
+  _TOD.seconds_trigger = nanoseconds;
   _TOD.is_set = true;
 
   _TOD_Activate();