Reorganisation of the source tree

[ghc-hetmet.git] / rts / Timer.c

diff --git a/rts/Timer.c b/rts/Timer.c
new file mode 100644 (file)
index 0000000..0bfea2d
--- /dev/null
+++ b/rts/Timer.c
@@ -0,0 +1,102 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 1995-2005
+ *
+ * Interval timer service for profiling and pre-emptive scheduling.
+ *
+ * ---------------------------------------------------------------------------*/
+
+/*
+ * The interval timer is used for profiling and for context switching in the
+ * threaded build. 
+ *
+ * This file defines the platform-independent view of interval timing, relying
+ * on platform-specific services to install and run the timers.
+ *
+ */
+#include "Rts.h"
+#include "RtsFlags.h"
+#include "Proftimer.h"
+#include "Schedule.h"
+#include "Timer.h"
+#include "Ticker.h"
+#include "Capability.h"
+
+/* ticks left before next pre-emptive context switch */
+static int ticks_to_ctxt_switch = 0;
+
+#if defined(THREADED_RTS)
+/* idle ticks left before we perform a GC */
+static int ticks_to_gc = 0;
+#endif
+
+/*
+ * Function: handle_tick()
+ *
+ * At each occurrence of a tick, the OS timer will invoke
+ * handle_tick().
+ */
+static
+void
+handle_tick(int unused STG_UNUSED)
+{
+#ifdef PROFILING
+  handleProfTick();
+#endif
+  if (RtsFlags.ConcFlags.ctxtSwitchTicks > 0) {
+      ticks_to_ctxt_switch--;
+      if (ticks_to_ctxt_switch <= 0) {
+         ticks_to_ctxt_switch = RtsFlags.ConcFlags.ctxtSwitchTicks;
+         context_switch = 1;   /* schedule a context switch */
+      }
+  }
+
+#if defined(THREADED_RTS)
+  /* 
+   * If we've been inactive for idleGCDelayTicks (set by +RTS
+   * -I), tell the scheduler to wake up and do a GC, to check
+   * for threads that are deadlocked.
+   */
+  switch (recent_activity) {
+  case ACTIVITY_YES:
+      recent_activity = ACTIVITY_MAYBE_NO;
+      ticks_to_gc = RtsFlags.GcFlags.idleGCDelayTicks;
+      break;
+  case ACTIVITY_MAYBE_NO:
+      if (ticks_to_gc == 0) break; /* 0 ==> no idle GC */
+      ticks_to_gc--;
+      if (ticks_to_gc == 0) {
+         ticks_to_gc = RtsFlags.GcFlags.idleGCDelayTicks;
+         recent_activity = ACTIVITY_INACTIVE;
+         blackholes_need_checking = rtsTrue;
+         /* hack: re-use the blackholes_need_checking flag */
+         
+         /* ToDo: this doesn't work.  Can't invoke
+          * pthread_cond_signal from a signal handler.
+          * Furthermore, we can't prod a capability that we
+          * might be holding.  What can we do?
+          */
+         prodOneCapability();
+      }
+      break;
+  default:
+      break;
+  }
+#endif
+}
+
+int
+startTimer(nat ms)
+{
+#ifdef PROFILING
+  initProfTimer();
+#endif
+
+  return startTicker(ms, handle_tick);
+}
+
+int
+stopTimer()
+{
+  return stopTicker();
+}