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-rw-r--r--rts/Timer.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/rts/Timer.c b/rts/Timer.c
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index 0000000000..0bfea2d6fd
--- /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();
+}