X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/759051fdbf8b3370705e05dac2e2d7525d882e4c..4ce77a5b1de05dae6092eae478b2a4397173d9c3:/ev.c

diff --git a/ev.c b/ev.c
index 3fc528a..acde504 100644
--- a/ev.c
+++ b/ev.c
@@ -218,9 +218,19 @@ extern "C" {
 
 /**/
 
+/*
+ * This is used to avoid floating point rounding problems.
+ * It is added to ev_rt_now when scheduling periodics
+ * to ensure progress, time-wise, even when rounding
+ * errors are against us.
+ * This value is good at least till the year 4000.
+ * Better solutions welcome.
+ */
+#define TIME_EPSILON  0.0001220703125 /* 1/8192 */
+
 #define MIN_TIMEJUMP  1. /* minimum timejump that gets detected (if monotonic clock available) */
 #define MAX_BLOCKTIME 59.743 /* never wait longer than this time (to detect time jumps) */
-/*#define CLEANUP_INTERVAL (MAX_BLOCKTIME * 5.) /* how often to try to free memory and re-check fds */
+/*#define CLEANUP_INTERVAL (MAX_BLOCKTIME * 5.) /* how often to try to free memory and re-check fds, TODO */
 
 #if __GNUC__ >= 3
 # define expect(expr,value)         __builtin_expect ((expr),(value))
@@ -1233,13 +1243,14 @@ periodics_reify (EV_P)
       /* first reschedule or stop timer */
       if (w->reschedule_cb)
         {
-          ((WT)w)->at = w->reschedule_cb (w, ev_rt_now + 0.0001);
+          ((WT)w)->at = w->reschedule_cb (w, ev_rt_now + TIME_EPSILON);
           assert (("ev_periodic reschedule callback returned time in the past", ((WT)w)->at > ev_rt_now));
           downheap ((WT *)periodics, periodiccnt, 0);
         }
       else if (w->interval)
         {
-          ((WT)w)->at = w->offset + floor ((ev_rt_now - w->offset) / w->interval + 1.) * w->interval;
+          ((WT)w)->at = w->offset + ceil ((ev_rt_now - w->offset) / w->interval) * w->interval;
+          if (((WT)w)->at - ev_rt_now <= TIME_EPSILON) ((WT)w)->at += w->interval;
           assert (("ev_periodic timeout in the past detected while processing timers, negative interval?", ((WT)w)->at > ev_rt_now));
           downheap ((WT *)periodics, periodiccnt, 0);
         }
@@ -1295,74 +1306,65 @@ idle_reify (EV_P)
 }
 #endif
 
-int inline_size
-time_update_monotonic (EV_P)
-{
-  mn_now = get_clock ();
-
-  if (expect_true (mn_now - now_floor < MIN_TIMEJUMP * .5))
-    {
-      ev_rt_now = rtmn_diff + mn_now;
-      return 0;
-    }
-  else
-    {
-      now_floor = mn_now;
-      ev_rt_now = ev_time ();
-      return 1;
-    }
-}
-
-void inline_size
-time_update (EV_P)
+void inline_speed
+time_update (EV_P_ ev_tstamp max_block)
 {
   int i;
 
 #if EV_USE_MONOTONIC
   if (expect_true (have_monotonic))
     {
-      if (time_update_monotonic (EV_A))
+      ev_tstamp odiff = rtmn_diff;
+
+      mn_now = get_clock ();
+
+      /* only fetch the realtime clock every 0.5*MIN_TIMEJUMP seconds */
+      /* interpolate in the meantime */
+      if (expect_true (mn_now - now_floor < MIN_TIMEJUMP * .5))
         {
-          ev_tstamp odiff = rtmn_diff;
-
-          /* loop a few times, before making important decisions.
-           * on the choice of "4": one iteration isn't enough,
-           * in case we get preempted during the calls to
-           * ev_time and get_clock. a second call is almost guaranteed
-           * to succeed in that case, though. and looping a few more times
-           * doesn't hurt either as we only do this on time-jumps or
-           * in the unlikely event of having been preempted here.
-           */
-          for (i = 4; --i; )
-            {
-              rtmn_diff = ev_rt_now - mn_now;
+          ev_rt_now = rtmn_diff + mn_now;
+          return;
+        }
+
+      now_floor = mn_now;
+      ev_rt_now = ev_time ();
 
-              if (fabs (odiff - rtmn_diff) < MIN_TIMEJUMP)
-                return; /* all is well */
+      /* loop a few times, before making important decisions.
+       * on the choice of "4": one iteration isn't enough,
+       * in case we get preempted during the calls to
+       * ev_time and get_clock. a second call is almost guaranteed
+       * to succeed in that case, though. and looping a few more times
+       * doesn't hurt either as we only do this on time-jumps or
+       * in the unlikely event of having been preempted here.
+       */
+      for (i = 4; --i; )
+        {
+          rtmn_diff = ev_rt_now - mn_now;
 
-              ev_rt_now = ev_time ();
-              mn_now    = get_clock ();
-              now_floor = mn_now;
-            }
+          if (fabs (odiff - rtmn_diff) < MIN_TIMEJUMP)
+            return; /* all is well */
+
+          ev_rt_now = ev_time ();
+          mn_now    = get_clock ();
+          now_floor = mn_now;
+        }
 
 # if EV_PERIODIC_ENABLE
-          periodics_reschedule (EV_A);
+      periodics_reschedule (EV_A);
 # endif
-          /* no timer adjustment, as the monotonic clock doesn't jump */
-          /* timers_reschedule (EV_A_ rtmn_diff - odiff) */
-        }
+      /* no timer adjustment, as the monotonic clock doesn't jump */
+      /* timers_reschedule (EV_A_ rtmn_diff - odiff) */
     }
   else
 #endif
     {
       ev_rt_now = ev_time ();
 
-      if (expect_false (mn_now > ev_rt_now || mn_now < ev_rt_now - MAX_BLOCKTIME - MIN_TIMEJUMP))
+      if (expect_false (mn_now > ev_rt_now || ev_rt_now > mn_now + max_block + MIN_TIMEJUMP))
         {
 #if EV_PERIODIC_ENABLE
           periodics_reschedule (EV_A);
 #endif
-
           /* adjust timers. this is easy, as the offset is the same for all of them */
           for (i = 0; i < timercnt; ++i)
             ((WT)timers [i])->at += ev_rt_now - mn_now;
@@ -1442,15 +1444,7 @@ ev_loop (EV_P_ int flags)
         else
           {
             /* update time to cancel out callback processing overhead */
-#if EV_USE_MONOTONIC
-            if (expect_true (have_monotonic))
-              time_update_monotonic (EV_A);
-            else
-#endif
-              {
-                ev_rt_now = ev_time ();
-                mn_now    = ev_rt_now;
-              }
+            time_update (EV_A_ 1e100);
 
             block = MAX_BLOCKTIME;
 
@@ -1473,10 +1467,10 @@ ev_loop (EV_P_ int flags)
 
         ++loop_count;
         backend_poll (EV_A_ block);
-      }
 
-      /* update ev_rt_now, do magic */
-      time_update (EV_A);
+        /* update ev_rt_now, do magic */
+        time_update (EV_A_ block);
+      }
 
       /* queue pending timers and reschedule them */
       timers_reify (EV_A); /* relative timers called last */