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/cvs/libev/ev.c
Revision: 1.4
Committed: Tue Oct 30 23:10:33 2007 UTC (16 years, 6 months ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.3: +129 -35 lines
Log Message:
much better

File Contents

# User Rev Content
1 root 1.1 #include <math.h>
2     #include <stdlib.h>
3    
4     #include <stdio.h>
5    
6 root 1.4 #include <assert.h>
7 root 1.1 #include <errno.h>
8     #include <sys/time.h>
9     #include <time.h>
10    
11     #ifdef CLOCK_MONOTONIC
12     # define HAVE_MONOTONIC 1
13     #endif
14    
15     #define HAVE_EPOLL 1
16     #define HAVE_REALTIME 1
17     #define HAVE_SELECT 0
18    
19 root 1.4 #define MIN_TIMEJUMP 1. /* minimum timejump that gets detected (if monotonic clock available) */
20 root 1.1 #define MAX_BLOCKTIME 60.
21    
22     #include "ev.h"
23    
24     struct ev_watcher {
25     EV_WATCHER (ev_watcher);
26     };
27    
28     struct ev_watcher_list {
29     EV_WATCHER_LIST (ev_watcher_list);
30     };
31    
32 root 1.4 static ev_tstamp now, diff; /* monotonic clock */
33 root 1.1 ev_tstamp ev_now;
34     int ev_method;
35    
36     static int have_monotonic; /* runtime */
37    
38     static ev_tstamp method_fudge; /* stupid epoll-returns-early bug */
39     static void (*method_reify)(void);
40     static void (*method_poll)(ev_tstamp timeout);
41    
42     ev_tstamp
43     ev_time (void)
44     {
45     #if HAVE_REALTIME
46     struct timespec ts;
47     clock_gettime (CLOCK_REALTIME, &ts);
48     return ts.tv_sec + ts.tv_nsec * 1e-9;
49     #else
50     struct timeval tv;
51     gettimeofday (&tv, 0);
52     return tv.tv_sec + tv.tv_usec * 1e-6;
53     #endif
54     }
55    
56     static ev_tstamp
57     get_clock (void)
58     {
59     #if HAVE_MONOTONIC
60     if (have_monotonic)
61     {
62     struct timespec ts;
63     clock_gettime (CLOCK_MONOTONIC, &ts);
64     return ts.tv_sec + ts.tv_nsec * 1e-9;
65     }
66     #endif
67    
68     return ev_time ();
69     }
70    
71     #define array_needsize(base,cur,cnt,init) \
72     if ((cnt) > cur) \
73     { \
74 root 1.2 int newcnt = cur ? cur << 1 : 16; \
75 root 1.1 fprintf (stderr, "resize(" # base ") from %d to %d\n", cur, newcnt);\
76     base = realloc (base, sizeof (*base) * (newcnt)); \
77     init (base + cur, newcnt - cur); \
78     cur = newcnt; \
79     }
80    
81     typedef struct
82     {
83     struct ev_io *head;
84     unsigned char wev, rev; /* want, received event set */
85     } ANFD;
86    
87     static ANFD *anfds;
88     static int anfdmax;
89    
90     static int *fdchanges;
91     static int fdchangemax, fdchangecnt;
92    
93     static void
94     anfds_init (ANFD *base, int count)
95     {
96     while (count--)
97     {
98     base->head = 0;
99     base->wev = base->rev = EV_NONE;
100     ++base;
101     }
102     }
103    
104     typedef struct
105     {
106     struct ev_watcher *w;
107     int events;
108     } ANPENDING;
109    
110     static ANPENDING *pendings;
111     static int pendingmax, pendingcnt;
112    
113     static void
114     event (struct ev_watcher *w, int events)
115     {
116     w->pending = ++pendingcnt;
117     array_needsize (pendings, pendingmax, pendingcnt, );
118     pendings [pendingcnt - 1].w = w;
119     pendings [pendingcnt - 1].events = events;
120     }
121    
122     static void
123     fd_event (int fd, int events)
124     {
125     ANFD *anfd = anfds + fd;
126     struct ev_io *w;
127    
128     for (w = anfd->head; w; w = w->next)
129     {
130     int ev = w->events & events;
131    
132     if (ev)
133     event ((struct ev_watcher *)w, ev);
134     }
135     }
136    
137 root 1.4 static struct ev_timer **atimers;
138     static int atimermax, atimercnt;
139    
140     static struct ev_timer **rtimers;
141     static int rtimermax, rtimercnt;
142 root 1.1
143     static void
144 root 1.4 upheap (struct ev_timer **timers, int k)
145 root 1.1 {
146     struct ev_timer *w = timers [k];
147    
148     while (k && timers [k >> 1]->at > w->at)
149     {
150     timers [k] = timers [k >> 1];
151     timers [k]->active = k + 1;
152     k >>= 1;
153     }
154    
155     timers [k] = w;
156     timers [k]->active = k + 1;
157    
158     }
159    
160     static void
161 root 1.4 downheap (struct ev_timer **timers, int N, int k)
162 root 1.1 {
163     struct ev_timer *w = timers [k];
164    
165 root 1.4 while (k < (N >> 1))
166 root 1.1 {
167     int j = k << 1;
168    
169 root 1.4 if (j + 1 < N && timers [j]->at > timers [j + 1]->at)
170 root 1.1 ++j;
171    
172     if (w->at <= timers [j]->at)
173     break;
174    
175     timers [k] = timers [j];
176 root 1.2 timers [k]->active = k + 1;
177 root 1.1 k = j;
178     }
179    
180     timers [k] = w;
181     timers [k]->active = k + 1;
182     }
183    
184     static struct ev_signal **signals;
185 root 1.4 static int signalmax;
186 root 1.1
187     static void
188     signals_init (struct ev_signal **base, int count)
189     {
190     while (count--)
191     *base++ = 0;
192     }
193    
194     #if HAVE_EPOLL
195     # include "ev_epoll.c"
196     #endif
197     #if HAVE_SELECT
198     # include "ev_select.c"
199     #endif
200    
201     int ev_init (int flags)
202     {
203     #if HAVE_MONOTONIC
204     {
205     struct timespec ts;
206     if (!clock_gettime (CLOCK_MONOTONIC, &ts))
207     have_monotonic = 1;
208     }
209     #endif
210    
211     ev_now = ev_time ();
212 root 1.4 now = get_clock ();
213     diff = ev_now - now;
214 root 1.1
215     #if HAVE_EPOLL
216     if (epoll_init (flags))
217     return ev_method;
218     #endif
219     #if HAVE_SELECT
220     if (select_init (flags))
221     return ev_method;
222     #endif
223    
224     ev_method = EVMETHOD_NONE;
225     return ev_method;
226     }
227    
228     void ev_prefork (void)
229     {
230     }
231    
232     void ev_postfork_parent (void)
233     {
234     }
235    
236     void ev_postfork_child (void)
237     {
238     #if HAVE_EPOLL
239     epoll_postfork_child ();
240     #endif
241     }
242    
243     static void
244     call_pending ()
245     {
246     int i;
247    
248     for (i = 0; i < pendingcnt; ++i)
249     {
250     ANPENDING *p = pendings + i;
251    
252     if (p->w)
253     {
254     p->w->pending = 0;
255     p->w->cb (p->w, p->events);
256     }
257     }
258    
259     pendingcnt = 0;
260     }
261    
262     static void
263 root 1.4 timers_reify (struct ev_timer **timers, int timercnt, ev_tstamp now)
264 root 1.1 {
265 root 1.4 while (timercnt && timers [0]->at <= now)
266 root 1.1 {
267     struct ev_timer *w = timers [0];
268    
269 root 1.4 /* first reschedule or stop timer */
270 root 1.1 if (w->repeat)
271     {
272     if (w->is_abs)
273 root 1.4 w->at += floor ((now - w->at) / w->repeat + 1.) * w->repeat;
274 root 1.1 else
275 root 1.4 w->at = now + w->repeat;
276    
277     assert (w->at > now);
278 root 1.1
279 root 1.4 downheap (timers, timercnt, 0);
280 root 1.1 }
281     else
282 root 1.4 {
283     evtimer_stop (w); /* nonrepeating: stop timer */
284     --timercnt; /* maybe pass by reference instead? */
285     }
286 root 1.1
287     event ((struct ev_watcher *)w, EV_TIMEOUT);
288     }
289     }
290    
291 root 1.4 static void
292     time_update ()
293     {
294     int i;
295     ev_now = ev_time ();
296    
297     if (have_monotonic)
298     {
299     ev_tstamp odiff = diff;
300    
301     /* detecting time jumps is much more difficult */
302     for (i = 2; --i; ) /* loop a few times, before making important decisions */
303     {
304     now = get_clock ();
305     diff = ev_now - now;
306    
307     if (fabs (odiff - diff) < MIN_TIMEJUMP)
308     return; /* all is well */
309    
310     ev_now = ev_time ();
311     }
312    
313     /* time jump detected, reschedule atimers */
314     for (i = 0; i < atimercnt; ++i)
315     {
316     struct ev_timer *w = atimers [i];
317     w->at += ceil ((ev_now - w->at) / w->repeat + 1.) * w->repeat;
318     }
319     }
320     else
321     {
322     if (now > ev_now || now < ev_now - MAX_BLOCKTIME - MIN_TIMEJUMP)
323     /* time jump detected, adjust rtimers */
324     for (i = 0; i < rtimercnt; ++i)
325     rtimers [i]->at += ev_now - now;
326    
327     now = ev_now;
328     }
329     }
330    
331 root 1.1 int ev_loop_done;
332    
333 root 1.4 void ev_loop (int flags)
334 root 1.1 {
335     double block;
336     ev_loop_done = flags & EVLOOP_ONESHOT;
337    
338     do
339     {
340     /* update fd-related kernel structures */
341     method_reify (); fdchangecnt = 0;
342    
343     /* calculate blocking time */
344     if (flags & EVLOOP_NONBLOCK)
345     block = 0.;
346     else
347     {
348 root 1.4 block = MAX_BLOCKTIME;
349    
350     if (rtimercnt)
351     {
352     ev_tstamp to = rtimers [0]->at - get_clock () + method_fudge;
353     if (block > to) block = to;
354     }
355    
356     if (atimercnt)
357     {
358     ev_tstamp to = atimers [0]->at - ev_time () + method_fudge;
359     if (block > to) block = to;
360     }
361    
362 root 1.1 if (block < 0.) block = 0.;
363     }
364    
365     method_poll (block);
366    
367 root 1.4 /* update ev_now, do magic */
368     time_update ();
369    
370 root 1.1 /* put pending timers into pendign queue and reschedule them */
371 root 1.4 /* absolute timers first */
372     timers_reify (atimers, atimercnt, ev_now);
373     /* relative timers second */
374     timers_reify (rtimers, rtimercnt, now);
375 root 1.1
376     call_pending ();
377     }
378     while (!ev_loop_done);
379     }
380    
381     static void
382     wlist_add (struct ev_watcher_list **head, struct ev_watcher_list *elem)
383     {
384     elem->next = *head;
385     *head = elem;
386     }
387    
388     static void
389     wlist_del (struct ev_watcher_list **head, struct ev_watcher_list *elem)
390     {
391     while (*head)
392     {
393     if (*head == elem)
394     {
395     *head = elem->next;
396     return;
397     }
398    
399     head = &(*head)->next;
400     }
401     }
402    
403     static void
404     ev_start (struct ev_watcher *w, int active)
405     {
406     w->pending = 0;
407     w->active = active;
408     }
409    
410     static void
411     ev_stop (struct ev_watcher *w)
412     {
413     if (w->pending)
414     pendings [w->pending - 1].w = 0;
415    
416     w->active = 0;
417     /* nop */
418     }
419    
420     void
421     evio_start (struct ev_io *w)
422     {
423     if (ev_is_active (w))
424     return;
425    
426     int fd = w->fd;
427    
428     ev_start ((struct ev_watcher *)w, 1);
429     array_needsize (anfds, anfdmax, fd + 1, anfds_init);
430     wlist_add ((struct ev_watcher_list **)&anfds[fd].head, (struct ev_watcher_list *)w);
431    
432     ++fdchangecnt;
433     array_needsize (fdchanges, fdchangemax, fdchangecnt, );
434     fdchanges [fdchangecnt - 1] = fd;
435     }
436    
437     void
438     evio_stop (struct ev_io *w)
439     {
440     if (!ev_is_active (w))
441     return;
442    
443     wlist_del ((struct ev_watcher_list **)&anfds[w->fd].head, (struct ev_watcher_list *)w);
444     ev_stop ((struct ev_watcher *)w);
445    
446     ++fdchangecnt;
447     array_needsize (fdchanges, fdchangemax, fdchangecnt, );
448     fdchanges [fdchangecnt - 1] = w->fd;
449     }
450    
451     void
452     evtimer_start (struct ev_timer *w)
453     {
454     if (ev_is_active (w))
455     return;
456    
457     if (w->is_abs)
458     {
459 root 1.2 /* this formula differs from the one in timer_reify becuse we do not round up */
460 root 1.1 if (w->repeat)
461     w->at += ceil ((ev_now - w->at) / w->repeat) * w->repeat;
462 root 1.4
463     ev_start ((struct ev_watcher *)w, ++atimercnt);
464     array_needsize (atimers, atimermax, atimercnt, );
465     atimers [atimercnt - 1] = w;
466     upheap (atimers, atimercnt - 1);
467 root 1.1 }
468     else
469 root 1.4 {
470     w->at += now;
471    
472     ev_start ((struct ev_watcher *)w, ++rtimercnt);
473     array_needsize (rtimers, rtimermax, rtimercnt, );
474     rtimers [rtimercnt - 1] = w;
475     upheap (rtimers, rtimercnt - 1);
476     }
477 root 1.1
478     }
479    
480     void
481     evtimer_stop (struct ev_timer *w)
482     {
483     if (!ev_is_active (w))
484     return;
485    
486 root 1.4 if (w->is_abs)
487 root 1.2 {
488 root 1.4 if (w->active < atimercnt--)
489     {
490     atimers [w->active - 1] = atimers [atimercnt];
491     downheap (atimers, atimercnt, w->active - 1);
492     }
493     }
494     else
495     {
496     if (w->active < rtimercnt--)
497     {
498     rtimers [w->active - 1] = rtimers [rtimercnt];
499     downheap (rtimers, rtimercnt, w->active - 1);
500     }
501 root 1.2 }
502    
503 root 1.1 ev_stop ((struct ev_watcher *)w);
504     }
505    
506     void
507     evsignal_start (struct ev_signal *w)
508     {
509     if (ev_is_active (w))
510     return;
511    
512     ev_start ((struct ev_watcher *)w, 1);
513     array_needsize (signals, signalmax, w->signum, signals_init);
514     wlist_add ((struct ev_watcher_list **)&signals [w->signum - 1], (struct ev_watcher_list *)w);
515     }
516    
517     void
518     evsignal_stop (struct ev_signal *w)
519     {
520     if (!ev_is_active (w))
521     return;
522    
523     wlist_del ((struct ev_watcher_list **)&signals [w->signum - 1], (struct ev_watcher_list *)w);
524     ev_stop ((struct ev_watcher *)w);
525     }
526    
527     /*****************************************************************************/
528     #if 1
529    
530     static void
531     sin_cb (struct ev_io *w, int revents)
532     {
533     fprintf (stderr, "sin %d, revents %d\n", w->fd, revents);
534     }
535    
536     static void
537     ocb (struct ev_timer *w, int revents)
538     {
539 root 1.4 //fprintf (stderr, "timer %f,%f (%x) (%f) d%p\n", w->at, w->repeat, revents, w->at - ev_time (), w->data);
540     evtimer_stop (w);
541     evtimer_start (w);
542 root 1.1 }
543    
544     int main (void)
545     {
546     struct ev_io sin;
547    
548     ev_init (0);
549    
550     evw_init (&sin, sin_cb, 55);
551     evio_set (&sin, 0, EV_READ);
552     evio_start (&sin);
553    
554 root 1.4 struct ev_timer t[10000];
555 root 1.2
556 root 1.4 #if 1
557 root 1.2 int i;
558 root 1.4 for (i = 0; i < 10000; ++i)
559 root 1.2 {
560     struct ev_timer *w = t + i;
561     evw_init (w, ocb, i);
562 root 1.4 evtimer_set_abs (w, drand48 (), 0.99775533);
563 root 1.2 evtimer_start (w);
564     if (drand48 () < 0.5)
565     evtimer_stop (w);
566     }
567 root 1.4 #endif
568    
569     struct ev_timer t1;
570     evw_init (&t1, ocb, 0);
571     evtimer_set_abs (&t1, 5, 10);
572     evtimer_start (&t1);
573 root 1.1
574     ev_loop (0);
575    
576     return 0;
577     }
578    
579     #endif
580    
581    
582    
583