rts/trace: Shrink tracing flags

2 files changed, 17 insertions, 15 deletions

diff --git a/rts/Trace.c b/rts/Trace.c
index f68a72cf2a..9f47147935 100644
--- a/rts/Trace.c
+++ b/rts/Trace.c
@@ -29,13 +29,13 @@
 #endif
 
 // events
-int TRACE_sched;
-int TRACE_gc;
-int TRACE_nonmoving_gc;
-int TRACE_spark_sampled;
-int TRACE_spark_full;
-int TRACE_user;
-int TRACE_cap;
+uint8_t TRACE_sched;
+uint8_t TRACE_gc;
+uint8_t TRACE_nonmoving_gc;
+uint8_t TRACE_spark_sampled;
+uint8_t TRACE_spark_full;
+uint8_t TRACE_user;
+uint8_t TRACE_cap;
 
 #if defined(THREADED_RTS)
 static Mutex trace_utx;
diff --git a/rts/Trace.h b/rts/Trace.h
index a1817e8b17..a4fa166594 100644
--- a/rts/Trace.h
+++ b/rts/Trace.h
@@ -66,14 +66,16 @@ enum CapsetType { CapsetTypeCustom = CAPSET_TYPE_CUSTOM,
 #define DEBUG_sparks      RtsFlags.DebugFlags.sparks
 #define DEBUG_compact     RtsFlags.DebugFlags.compact
 
-// events
-extern int TRACE_sched;
-extern int TRACE_gc;
-extern int TRACE_spark_sampled;
-extern int TRACE_spark_full;
-/* extern int TRACE_user; */  // only used in Trace.c
-extern int TRACE_cap;
-extern int TRACE_nonmoving_gc;
+// Event-enabled flags
+// These semantically booleans but we use a dense packing to minimize their
+// cache impact.
+extern uint8_t TRACE_sched;
+extern uint8_t TRACE_gc;
+extern uint8_t TRACE_nonmoving_gc;
+extern uint8_t TRACE_spark_sampled;
+extern uint8_t TRACE_spark_full;
+extern uint8_t TRACE_cap;
+/* extern uint8_t TRACE_user; */  // only used in Trace.c
 
 // -----------------------------------------------------------------------------
 // Posting events