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Comparing libev/ev.c (file contents):
Revision 1.174 by root, Tue Dec 11 03:18:33 2007 UTC vs.
Revision 1.178 by root, Tue Dec 11 18:36:11 2007 UTC

… …
216# include <sys/inotify.h> 216# include <sys/inotify.h>
217#endif 217#endif
218 218
219/**/ 219/**/
220 220
221/*
222 * This is used to avoid floating point rounding problems.
223 * It is added to ev_rt_now when scheduling periodics
224 * to ensure progress, time-wise, even when rounding
225 * errors are against us.
226 * This value is good at least till the year 4000.
227 * Better solutions welcome.
228 */
229#define TIME_EPSILON 0.0001220703125 /* 1/8192 */
230
221#define MIN_TIMEJUMP 1. /* minimum timejump that gets detected (if monotonic clock available) */ 231#define MIN_TIMEJUMP 1. /* minimum timejump that gets detected (if monotonic clock available) */
222#define MAX_BLOCKTIME 59.743 /* never wait longer than this time (to detect time jumps) */ 232#define MAX_BLOCKTIME 59.743 /* never wait longer than this time (to detect time jumps) */
223/*#define CLEANUP_INTERVAL (MAX_BLOCKTIME * 5.) /* how often to try to free memory and re-check fds */ 233/*#define CLEANUP_INTERVAL (MAX_BLOCKTIME * 5.) /* how often to try to free memory and re-check fds, TODO */
224 234
225#if __GNUC__ >= 3 235#if __GNUC__ >= 3
226# define expect(expr,value) __builtin_expect ((expr),(value)) 236# define expect(expr,value) __builtin_expect ((expr),(value))
227# define noinline __attribute__ ((noinline)) 237# define noinline __attribute__ ((noinline))
228#else 238#else
… …
1231 /*assert (("inactive timer on periodic heap detected", ev_is_active (w)));*/ 1241 /*assert (("inactive timer on periodic heap detected", ev_is_active (w)));*/
1232 1242
1233 /* first reschedule or stop timer */ 1243 /* first reschedule or stop timer */
1234 if (w->reschedule_cb) 1244 if (w->reschedule_cb)
1235 { 1245 {
1236 ((WT)w)->at = w->reschedule_cb (w, ev_rt_now + 0.0001220703125 /* 1/8192 */); 1246 ((WT)w)->at = w->reschedule_cb (w, ev_rt_now + TIME_EPSILON);
1237 assert (("ev_periodic reschedule callback returned time in the past", ((WT)w)->at > ev_rt_now)); 1247 assert (("ev_periodic reschedule callback returned time in the past", ((WT)w)->at > ev_rt_now));
1238 downheap ((WT *)periodics, periodiccnt, 0); 1248 downheap ((WT *)periodics, periodiccnt, 0);
1239 } 1249 }
1240 else if (w->interval) 1250 else if (w->interval)
1241 { 1251 {
1242 ((WT)w)->at = w->offset + floor ((ev_rt_now - w->offset) / w->interval + 1.) * w->interval; 1252 ((WT)w)->at = w->offset + ceil ((ev_rt_now - w->offset) / w->interval) * w->interval;
1253 if (((WT)w)->at - ev_rt_now <= TIME_EPSILON) ((WT)w)->at += w->interval;
1243 assert (("ev_periodic timeout in the past detected while processing timers, negative interval?", ((WT)w)->at > ev_rt_now)); 1254 assert (("ev_periodic timeout in the past detected while processing timers, negative interval?", ((WT)w)->at > ev_rt_now));
1244 downheap ((WT *)periodics, periodiccnt, 0); 1255 downheap ((WT *)periodics, periodiccnt, 0);
1245 } 1256 }
1246 else 1257 else
1247 ev_periodic_stop (EV_A_ w); /* nonrepeating: stop timer */ 1258 ev_periodic_stop (EV_A_ w); /* nonrepeating: stop timer */
… …
1293 } 1304 }
1294 } 1305 }
1295} 1306}
1296#endif 1307#endif
1297 1308
1298int inline_size 1309void inline_speed
1299time_update_monotonic (EV_P) 1310time_update (EV_P_ ev_tstamp max_block)
1300{ 1311{
1312 int i;
1313
1314#if EV_USE_MONOTONIC
1315 if (expect_true (have_monotonic))
1316 {
1317 ev_tstamp odiff = rtmn_diff;
1318
1301 mn_now = get_clock (); 1319 mn_now = get_clock ();
1302 1320
1321 /* only fetch the realtime clock every 0.5*MIN_TIMEJUMP seconds */
1322 /* interpolate in the meantime */
1303 if (expect_true (mn_now - now_floor < MIN_TIMEJUMP * .5)) 1323 if (expect_true (mn_now - now_floor < MIN_TIMEJUMP * .5))
1304 { 1324 {
1305 ev_rt_now = rtmn_diff + mn_now; 1325 ev_rt_now = rtmn_diff + mn_now;
1306 return 0; 1326 return;
1307 } 1327 }
1308 else 1328
1309 {
1310 now_floor = mn_now; 1329 now_floor = mn_now;
1311 ev_rt_now = ev_time (); 1330 ev_rt_now = ev_time ();
1312 return 1;
1313 }
1314}
1315 1331
1316void inline_size 1332 /* loop a few times, before making important decisions.
1317time_update (EV_P) 1333 * on the choice of "4": one iteration isn't enough,
1318{ 1334 * in case we get preempted during the calls to
1319 int i; 1335 * ev_time and get_clock. a second call is almost guaranteed
1320 1336 * to succeed in that case, though. and looping a few more times
1321#if EV_USE_MONOTONIC 1337 * doesn't hurt either as we only do this on time-jumps or
1322 if (expect_true (have_monotonic)) 1338 * in the unlikely event of having been preempted here.
1323 { 1339 */
1324 if (time_update_monotonic (EV_A)) 1340 for (i = 4; --i; )
1325 { 1341 {
1326 ev_tstamp odiff = rtmn_diff;
1327
1328 /* loop a few times, before making important decisions.
1329 * on the choice of "4": one iteration isn't enough,
1330 * in case we get preempted during the calls to
1331 * ev_time and get_clock. a second call is almost guaranteed
1332 * to succeed in that case, though. and looping a few more times
1333 * doesn't hurt either as we only do this on time-jumps or
1334 * in the unlikely event of having been preempted here.
1335 */
1336 for (i = 4; --i; )
1337 {
1338 rtmn_diff = ev_rt_now - mn_now; 1342 rtmn_diff = ev_rt_now - mn_now;
1339 1343
1340 if (fabs (odiff - rtmn_diff) < MIN_TIMEJUMP) 1344 if (fabs (odiff - rtmn_diff) < MIN_TIMEJUMP)
1341 return; /* all is well */ 1345 return; /* all is well */
1342 1346
1343 ev_rt_now = ev_time (); 1347 ev_rt_now = ev_time ();
1344 mn_now = get_clock (); 1348 mn_now = get_clock ();
1345 now_floor = mn_now; 1349 now_floor = mn_now;
1346 } 1350 }
1347 1351
1348# if EV_PERIODIC_ENABLE 1352# if EV_PERIODIC_ENABLE
1349 periodics_reschedule (EV_A); 1353 periodics_reschedule (EV_A);
1350# endif 1354# endif
1351 /* no timer adjustment, as the monotonic clock doesn't jump */ 1355 /* no timer adjustment, as the monotonic clock doesn't jump */
1352 /* timers_reschedule (EV_A_ rtmn_diff - odiff) */ 1356 /* timers_reschedule (EV_A_ rtmn_diff - odiff) */
1353 }
1354 } 1357 }
1355 else 1358 else
1356#endif 1359#endif
1357 { 1360 {
1358 ev_rt_now = ev_time (); 1361 ev_rt_now = ev_time ();
1359 1362
1360 if (expect_false (mn_now > ev_rt_now || mn_now < ev_rt_now - MAX_BLOCKTIME - MIN_TIMEJUMP)) 1363 if (expect_false (mn_now > ev_rt_now || ev_rt_now > mn_now + max_block + MIN_TIMEJUMP))
1361 { 1364 {
1362#if EV_PERIODIC_ENABLE 1365#if EV_PERIODIC_ENABLE
1363 periodics_reschedule (EV_A); 1366 periodics_reschedule (EV_A);
1364#endif 1367#endif
1365
1366 /* adjust timers. this is easy, as the offset is the same for all of them */ 1368 /* adjust timers. this is easy, as the offset is the same for all of them */
1367 for (i = 0; i < timercnt; ++i) 1369 for (i = 0; i < timercnt; ++i)
1368 ((WT)timers [i])->at += ev_rt_now - mn_now; 1370 ((WT)timers [i])->at += ev_rt_now - mn_now;
1369 } 1371 }
1370 1372
… …
1440 if (expect_false (flags & EVLOOP_NONBLOCK || idleall || !activecnt)) 1442 if (expect_false (flags & EVLOOP_NONBLOCK || idleall || !activecnt))
1441 block = 0.; /* do not block at all */ 1443 block = 0.; /* do not block at all */
1442 else 1444 else
1443 { 1445 {
1444 /* update time to cancel out callback processing overhead */ 1446 /* update time to cancel out callback processing overhead */
1445#if EV_USE_MONOTONIC
1446 if (expect_true (have_monotonic))
1447 time_update_monotonic (EV_A); 1447 time_update (EV_A_ 1e100);
1448 else
1449#endif
1450 {
1451 ev_rt_now = ev_time ();
1452 mn_now = ev_rt_now;
1453 }
1454 1448
1455 block = MAX_BLOCKTIME; 1449 block = MAX_BLOCKTIME;
1456 1450
1457 if (timercnt) 1451 if (timercnt)
1458 { 1452 {
… …
1471 if (expect_false (block < 0.)) block = 0.; 1465 if (expect_false (block < 0.)) block = 0.;
1472 } 1466 }
1473 1467
1474 ++loop_count; 1468 ++loop_count;
1475 backend_poll (EV_A_ block); 1469 backend_poll (EV_A_ block);
1470
1471 /* update ev_rt_now, do magic */
1472 time_update (EV_A_ block);
1476 } 1473 }
1477
1478 /* update ev_rt_now, do magic */
1479 time_update (EV_A);
1480 1474
1481 /* queue pending timers and reschedule them */ 1475 /* queue pending timers and reschedule them */
1482 timers_reify (EV_A); /* relative timers called last */ 1476 timers_reify (EV_A); /* relative timers called last */
1483#if EV_PERIODIC_ENABLE 1477#if EV_PERIODIC_ENABLE
1484 periodics_reify (EV_A); /* absolute timers called first */ 1478 periodics_reify (EV_A); /* absolute timers called first */

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