[project @ 2001-11-13 13:38:02 by simonmar]

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

diff --git a/ghc/rts/Itimer.c b/ghc/rts/Itimer.c
index 9117157..c51de4f 100644 (file)
--- a/ghc/rts/Itimer.c
+++ b/ghc/rts/Itimer.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Itimer.c,v 1.15 2000/07/17 15:09:35 rrt Exp $
+ * $Id: Itimer.c,v 1.24 2001/11/13 13:38:02 simonmar Exp $
  *
  * (c) The GHC Team, 1995-1999
  *
@@ -18,11 +18,11 @@
  * to support.  So much for standards.
  */
 
-#if !defined(_AIX)
-# define NON_POSIX_SOURCE
-#endif
+/* This is not posix compliant. */
+/* #include "PosixSource.h" */
 
 #include "Rts.h"
+#include "RtsFlags.h"
 #include "Itimer.h"
 #include "Proftimer.h"
 #include "Schedule.h"
@@ -45,18 +45,13 @@
  
 lnat total_ticks = 0;
 
-static
-void
-#if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
-CALLBACK
-#endif
-handle_tick(int unused STG_UNUSED);
+/* ticks left before next pre-emptive context switch */
+int ticks_to_ctxt_switch = 0;
 
 /* -----------------------------------------------------------------------------
    Tick handler
 
-   We use the ticker for two things: supporting threadDelay, and time
-   profiling.
+   We use the ticker for time profiling.
 
    SMP note: this signal could be delivered to *any* thread.  We have
    to ensure that it doesn't matter which thread actually runs the
@@ -67,8 +62,11 @@ static
 void
 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
 CALLBACK
-#endif
+handle_tick(UINT uID STG_UNUSED, UINT uMsg STG_UNUSED, DWORD dwUser STG_UNUSED,
+           DWORD dw1 STG_UNUSED, DWORD d STG_UNUSED)
+#else
 handle_tick(int unused STG_UNUSED)
+#endif
 {
   total_ticks++;
 
@@ -76,10 +74,13 @@ handle_tick(int unused STG_UNUSED)
   handleProfTick();
 #endif
 
-  /* For threadDelay etc., see Select.c */
-  ticks_since_select++;
-
-  context_switch = 1;
+  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 */
+      }
+  }
 }
 
 
@@ -96,43 +97,36 @@ handle_tick(int unused STG_UNUSED)
 
 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
 
-/*
-  vtalrm_handler is assigned and set up in Signals.c
-
-  vtalrm_id (defined in Signals.c) holds
-  the system id for the current timer (used to 
-  later block/kill it.)
-*/
-extern nat vtalrm_id;
-TIMECALLBACK *vtalrm_cback;
- 
+LPTIMECALLBACK vtalrm_cback;
+
 nat
 initialize_virtual_timer(nat ms)
 {
-# ifdef PROFILING
   /* On Win32 setups that don't have support for
      setitimer(), we use the MultiMedia API's timer
      support.
      
-     As the delivery of ticks isn't free, we only
-     enable it if we really needed, i.e., when profiling.
-     (the RTS now also needs timer ticks to implement
-     threadDelay in non-profiling mode, but the pure
-     Win32 port doesn't support that.....yet.)
+     The delivery of ticks isn't free; the performance hit should be checked.
   */
-  unsigned int delay,vtalrm_id;
+  unsigned int delay;
+  static unsigned int vtalrm_id;
  
-  delay = timeBeginPeriod(1);
-  if (delay == TIMERR_NOCANDO) { /* error of some sort. */
-     return delay;
+  if (ms) {
+    delay = timeBeginPeriod(1);
+    if (delay == TIMERR_NOCANDO) { /* error of some sort. */
+      return delay;
+    }
+    vtalrm_id =
+      timeSetEvent(ms,      /* event every `delay' milliseconds. */
+                  1,       /* precision is within 1 ms */
+                  vtalrm_cback,
+                  TIME_CALLBACK_FUNCTION,     /* ordinary callback */
+                  TIME_PERIODIC);
+  } else {
+    timeKillEvent(vtalrm_id);
+    timeEndPeriod(1);
   }
-  vtalrm_id =
-    timeSetEvent(ms,     /* event every `delay' milliseconds. */
-               1,       /* precision is within 5 millisecs. */
-               (LPTIMECALLBACK)vtalrm_cback,
-               0,
-               TIME_PERIODIC);
-# endif
+
   return 0;
 }
  
@@ -147,6 +141,8 @@ initialize_virtual_timer(nat ms)
 # else
     struct itimerval it;
 
+    timestamp = getourtimeofday();
+
     it.it_value.tv_sec = ms / 1000;
     it.it_value.tv_usec = 1000 * (ms - (1000 * it.it_value.tv_sec));
     it.it_interval = it.it_value;
@@ -165,6 +161,8 @@ initialize_virtual_timer(nat ms)
     struct itimerspec it;
     timer_t tid;
 
+    timestamp = getourtimeofday();
+
     se.sigev_notify = SIGEV_SIGNAL;
     se.sigev_signo = SIGVTALRM;
     se.sigev_value.sival_int = SIGVTALRM;
@@ -223,12 +221,22 @@ unblock_vtalrm_signal(void)
 }
 #endif
 
-#if !defined(HAVE_SETITIMER) && !defined(mingw32_TARGET_OS)
+/* gettimeofday() takes around 1us on our 500MHz PIII.  Since we're
+ * only calling it 50 times/s, it shouldn't have any great impact.
+ */
+#if !defined(mingw32_TARGET_OS)
 unsigned int 
 getourtimeofday(void)
 {
   struct timeval tv;
   gettimeofday(&tv, (struct timezone *) NULL);
-  return (tv.tv_sec * 1000000 + tv.tv_usec);
+  return (tv.tv_sec * TICK_FREQUENCY +
+         tv.tv_usec * TICK_FREQUENCY / 1000000);
+}
+#else
+unsigned int
+getourtimeofday(void)
+{
+  return ((unsigned int)GetTickCount() * TICK_FREQUENCY) / 1000;
 }
 #endif