[ViewVC] Diff of: cvs/libev/ev.c

Comparing libev/ev.c (file contents):
Revision 1.369 by root, Sun Jan 23 18:53:06 2011 UTC vs.
Revision 1.377 by root, Wed Jun 8 13:11:55 2011 UTC

  * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modifica-
  * tion, are permitted provided that the following conditions are met:
  *
  *   1.  Redistributions of source code must retain the above copyright notice,
  *       this list of conditions and the following disclaimer.
  *
  *   2.  Redistributions in binary form must reproduce the above copyright
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 # ifdef EV_CONFIG_H
 #  include EV_CONFIG_H
 # else
 #  include "config.h"
 # endif
+#if HAVE_FLOOR
+# ifndef EV_USE_FLOOR
+#  define EV_USE_FLOOR 1
+# endif
+#endif
 # if HAVE_CLOCK_SYSCALL
 #  ifndef EV_USE_CLOCK_SYSCALL
 #   define EV_USE_CLOCK_SYSCALL 1
 #   ifndef EV_USE_REALTIME
 #  define EV_USE_EVENTFD 0
 # endif
 #endif
-#include <math.h>
 #include <stdlib.h>
 #include <string.h>
 #include <fcntl.h>
 #include <stddef.h>
 /* to make it compile regardless, just remove the above line, */
 /* but consider reporting it, too! :) */
 # define EV_NSIG 65
 #endif
+#ifndef EV_USE_FLOOR
+# define EV_USE_FLOOR 0
+#endif
 #ifndef EV_USE_CLOCK_SYSCALL
 # if __linux && __GLIBC__ >= 2
 #  define EV_USE_CLOCK_SYSCALL EV_FEATURE_OS
 # else
 #  define EV_USE_CLOCK_SYSCALL 0
 # undef EV_USE_INOTIFY
 # define EV_USE_INOTIFY 0
 #endif
 #if !EV_USE_NANOSLEEP
-# ifndef _WIN32
+/* hp-ux has it in sys/time.h, which we unconditionally include above */
+# if !defined(_WIN32) && !defined(__hpux)
 #  include <sys/select.h>
 # endif
 #endif
 #if EV_USE_INOTIFY
 #else
 # define EV_FREQUENT_CHECK do { } while (0)
 #endif
 /*
- * This is used to avoid floating point rounding problems.
+ * This is used to work around 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_INTERVAL  0.0001220703125 /* 1/2**13, good till 4000 */
+/*#define MIN_INTERVAL  0.00000095367431640625 /* 1/2**20, good till 2200 */
 #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 EV_TV_SET(tv,t) do { tv.tv_sec = (long)t; tv.tv_usec = (long)((t - tv.tv_sec) * 1e6); } while (0)
 # define EV_WIN32_CLOSE_FD(fd) close (fd)
 #endif
 #ifdef _WIN32
 # include "ev_win32.c"
+#endif
+/*****************************************************************************/
+/* define a suitable floor function (only used by periodics atm) */
+#if EV_USE_FLOOR
+# include <math.h>
+# define ev_floor(v) floor (v)
+#else
+#include <float.h>
+/* a floor() replacement function, should be independent of ev_tstamp type */
+static ev_tstamp noinline
+ev_floor (ev_tstamp v)
+{
+  /* the choice of shift factor is not terribly important */
+#if FLT_RADIX != 2 /* assume FLT_RADIX == 10 */
+  const ev_tstamp shift = sizeof (unsigned long) >= 8 ? 10000000000000000000. : 1000000000.;
+#else
+  const ev_tstamp shift = sizeof (unsigned long) >= 8 ? 18446744073709551616. : 4294967296.;
+#endif
+  /* argument too large for an unsigned long? */
+  if (expect_false (v >= shift))
+    {
+      ev_tstamp f;
+      if (v == v - 1.)
+        return v; /* very large number */
+      f = shift * ev_floor (v * (1. / shift));
+      return f + ev_floor (v - f);
+    }
+  /* special treatment for negative args? */
+  if (expect_false (v < 0.))
+    {
+      ev_tstamp f = -ev_floor (-v);
+      return f - (f == v ? 0 : 1);
+    }
+  /* fits into an unsigned long */
+  return (unsigned long)v;
+}
 #endif
 /*****************************************************************************/
 #ifdef __linux
       select (0, 0, 0, 0, &tv);
 #endif
     }
 }
-inline_speed int
-ev_timeout_to_ms (ev_tstamp timeout)
-{
-  int ms = timeout * 1000. + .999999;
-  return expect_true (ms) ? ms : timeout < 1e-6 ? 0 : 1;
-}
 /*****************************************************************************/
 #define MALLOC_ROUND 4096 /* prefer to allocate in chunks of this size, must be 2**n and >> 4 longs */
 /* find a suitable new size for the given array, */
 inline_size void
 fd_reify (EV_P)
 {
   int i;
+#if EV_SELECT_IS_WINSOCKET || EV_USE_IOCP
+  for (i = 0; i < fdchangecnt; ++i)
+    {
+      int fd = fdchanges [i];
+      ANFD *anfd = anfds + fd;
+      if (anfd->reify & EV__IOFDSET && anfd->head)
+        {
+          SOCKET handle = EV_FD_TO_WIN32_HANDLE (fd);
+          if (handle != anfd->handle)
+            {
+              unsigned long arg;
+              assert (("libev: only socket fds supported in this configuration", ioctlsocket (handle, FIONREAD, &arg) == 0));
+              /* handle changed, but fd didn't - we need to do it in two steps */
+              backend_modify (EV_A_ fd, anfd->events, 0);
+              anfd->events = 0;
+              anfd->handle = handle;
+            }
+        }
+    }
+#endif
   for (i = 0; i < fdchangecnt; ++i)
     {
       int fd = fdchanges [i];
       ANFD *anfd = anfds + fd;
       ev_io *w;
       unsigned char o_events = anfd->events;
       unsigned char o_reify  = anfd->reify;
       anfd->reify  = 0;
-#if EV_SELECT_IS_WINSOCKET || EV_USE_IOCP
-      if (o_reify & EV__IOFDSET)
-        {
-          unsigned long arg;
-          anfd->handle = EV_FD_TO_WIN32_HANDLE (fd);
-          assert (("libev: only socket fds supported in this configuration", ioctlsocket (anfd->handle, FIONREAD, &arg) == 0));
-          printf ("oi %d %x\n", fd, anfd->handle);//D
-        }
-#endif
       /*if (expect_true (o_reify & EV_ANFD_REIFY)) probably a deoptimisation */
         {
           anfd->events = 0;
       read (evpipe [0], &dummy, 1);
     }
 #if EV_SIGNAL_ENABLE
   if (sig_pending)
     {
       sig_pending = 0;
       for (i = EV_NSIG - 1; i--; )
         if (expect_false (signals [i].pending))
           ev_feed_signal_event (EV_A_ i + 1);
       feed_reverse_done (EV_A_ EV_TIMER);
     }
 }
 #if EV_PERIODIC_ENABLE
+static void noinline
+periodic_recalc (EV_P_ ev_periodic *w)
+{
+  ev_tstamp interval = w->interval > MIN_INTERVAL ? w->interval : MIN_INTERVAL;
+  ev_tstamp at = w->offset + interval * ev_floor ((ev_rt_now - w->offset) / interval);
+  /* the above almost always errs on the low side */
+  while (at <= ev_rt_now)
+    {
+      ev_tstamp nat = at + w->interval;
+      /* when resolution fails us, we use ev_rt_now */
+      if (expect_false (nat == at))
+        {
+          at = ev_rt_now;
+          break;
+        }
+      at = nat;
+    }
+  ev_at (w) = at;
+}
 /* make periodics pending */
 inline_size void
 periodics_reify (EV_P)
 {
   EV_FREQUENT_CHECK;
               ANHE_at_cache (periodics [HEAP0]);
               downheap (periodics, periodiccnt, HEAP0);
             }
           else if (w->interval)
             {
-              ev_at (w) = w->offset + ceil ((ev_rt_now - w->offset) / w->interval) * w->interval;
+              periodic_recalc (EV_A_ w);
-              /* if next trigger time is not sufficiently in the future, put it there */
-              /* this might happen because of floating point inexactness */
-              if (ev_at (w) - ev_rt_now < TIME_EPSILON)
-                {
-                  ev_at (w) += w->interval;
-                  /* if interval is unreasonably low we might still have a time in the past */
-                  /* so correct this. this will make the periodic very inexact, but the user */
-                  /* has effectively asked to get triggered more often than possible */
-                  if (ev_at (w) < ev_rt_now)
-                    ev_at (w) = ev_rt_now;
-                }
               ANHE_at_cache (periodics [HEAP0]);
               downheap (periodics, periodiccnt, HEAP0);
             }
           else
             ev_periodic_stop (EV_A_ w); /* nonrepeating: stop timer */
       ev_periodic *w = (ev_periodic *)ANHE_w (periodics [i]);
       if (w->reschedule_cb)
         ev_at (w) = w->reschedule_cb (w, ev_rt_now);
       else if (w->interval)
-        ev_at (w) = w->offset + ceil ((ev_rt_now - w->offset) / w->interval) * w->interval;
+        periodic_recalc (EV_A_ w);
       ANHE_at_cache (periodics [i]);
     }
   reheap (periodics, periodiccnt);
        * 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; )
         {
+          ev_tstamp diff;
           rtmn_diff = ev_rt_now - mn_now;
+          diff = odiff - rtmn_diff;
-          if (expect_true (fabs (odiff - rtmn_diff) < MIN_TIMEJUMP))
+          if (expect_true ((diff < 0. ? -diff : diff) < MIN_TIMEJUMP))
             return; /* all is well */
           ev_rt_now = ev_time ();
           mn_now    = get_clock ();
           now_floor = mn_now;
           {
             waittime = MAX_BLOCKTIME;
             if (timercnt)
               {
-                ev_tstamp to = ANHE_at (timers [HEAP0]) - mn_now + backend_fudge;
+                ev_tstamp to = ANHE_at (timers [HEAP0]) - mn_now;
                 if (waittime > to) waittime = to;
               }
 #if EV_PERIODIC_ENABLE
             if (periodiccnt)
               {
-                ev_tstamp to = ANHE_at (periodics [HEAP0]) - ev_rt_now + backend_fudge;
+                ev_tstamp to = ANHE_at (periodics [HEAP0]) - ev_rt_now;
                 if (waittime > to) waittime = to;
               }
 #endif
             /* don't let timeouts decrease the waittime below timeout_blocktime */
             if (expect_false (waittime < timeout_blocktime))
               waittime = timeout_blocktime;
+            /* at this point, we NEED to wait, so we have to ensure */
+            /* to pass a minimum nonzero value to the backend */
+            if (expect_false (waittime < backend_mintime))
+              waittime = backend_mintime;
             /* extra check because io_blocktime is commonly 0 */
             if (expect_false (io_blocktime))
               {
                 sleeptime = io_blocktime - (mn_now - prev_mn_now);
-                if (sleeptime > waittime - backend_fudge)
+                if (sleeptime > waittime - backend_mintime)
-                  sleeptime = waittime - backend_fudge;
+                  sleeptime = waittime - backend_mintime;
                 if (expect_true (sleeptime > 0.))
                   {
                     ev_sleep (sleeptime);
                     waittime -= sleeptime;
   if (w->reschedule_cb)
     ev_at (w) = w->reschedule_cb (w, ev_rt_now);
   else if (w->interval)
     {
       assert (("libev: ev_periodic_start called with negative interval value", w->interval >= 0.));
-      /* this formula differs from the one in periodic_reify because we do not always round up */
+      periodic_recalc (EV_A_ w);
-      ev_at (w) = w->offset + ceil ((ev_rt_now - w->offset) / w->interval) * w->interval;
     }
   else
     ev_at (w) = w->offset;
   EV_FREQUENT_CHECK;
               if (!pend || pend == path)
                 break;
               *pend = 0;
               w->wd = inotify_add_watch (fs_fd, path, mask);
             }
           while (w->wd < 0 && (errno == ENOENT || errno == EACCES));
         }
     }
   if (w->wd >= 0)

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Comparing libev/ev.c (file contents): Revision 1.369 by root, Sun Jan 23 18:53:06 2011 UTC vs. Revision 1.377 by root, Wed Jun 8 13:11:55 2011 UTC

Diff Legend

Comparing libev/ev.c (file contents):
Revision 1.369 by root, Sun Jan 23 18:53:06 2011 UTC vs.
Revision 1.377 by root, Wed Jun 8 13:11:55 2011 UTC