root/branches/libffado-2.0/src/libieee1394/CycleTimerHelper.cpp

Revision 1525, 29.9 kB (checked in by ppalmers, 12 years ago)

- Allow to specify the DLL bandwidths for the CycleTimerHelper? and the TimestampedBuffer? in absolute units (Hz). This ensures samplerate-independent operation
- Reduce the default DLL bandwidth for the TimestampedBuffer?'s. This improves timestamp timing with a factor 10x, which should benefit especially the timing sensitive devices (MOTU).
- Allow to specify the DLL bandwith and other transmit settings through the configuration file
- Implement a sanity check for the instantanous samplerate to detect bogus timestamp processing

Line 
1 /*
2  * Copyright (C) 2005-2008 by Pieter Palmers
3  *
4  * This file is part of FFADO
5  * FFADO = Free Firewire (pro-)audio drivers for linux
6  *
7  * FFADO is based upon FreeBoB
8  *
9  * This program is free software: you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation, either version 2 of the License, or
12  * (at your option) version 3 of the License.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
21  *
22  */
23
24 #include "config.h"
25
26 #include "CycleTimerHelper.h"
27 #include "ieee1394service.h"
28 #include "libutil/PosixThread.h"
29 #include "libutil/PosixMutex.h"
30 #include "libutil/Atomic.h"
31 #include "libutil/Watchdog.h"
32
33 #define DLL_PI        (3.141592653589793238)
34 #define DLL_2PI       (2 * DLL_PI)
35 #define DLL_SQRT2     (1.414213562373095049)
36
37 IMPL_DEBUG_MODULE( CycleTimerHelper, CycleTimerHelper, DEBUG_LEVEL_NORMAL );
38
39 CycleTimerHelper::CycleTimerHelper(Ieee1394Service &parent, unsigned int update_period_us)
40     : m_Parent ( parent )
41     , m_ticks_per_update ( ((uint64_t)TICKS_PER_SECOND) * ((uint64_t)update_period_us) / 1000000ULL )
42     , m_usecs_per_update ( update_period_us )
43     , m_avg_wakeup_delay ( 0.0 )
44     , m_dll_e2 ( 0.0 )
45     , m_current_time_usecs ( 0 )
46     , m_next_time_usecs ( 0 )
47     , m_current_time_ticks ( 0 )
48     , m_next_time_ticks ( 0 )
49     , m_first_run ( true )
50     , m_sleep_until ( 0 )
51     , m_cycle_timer_prev ( 0 )
52     , m_cycle_timer_ticks_prev ( 0 )
53     , m_current_shadow_idx ( 0 )
54     , m_Thread ( NULL )
55     , m_realtime ( false )
56     , m_priority ( 0 )
57     , m_update_lock( new Util::PosixMutex("CTRUPD") )
58     , m_busreset_functor ( NULL)
59     , m_unhandled_busreset ( false )
60 {
61     debugOutput( DEBUG_LEVEL_VERBOSE, "Create %p...\n", this);
62
63     double bw_rel = IEEE1394SERVICE_CYCLETIMER_DLL_BANDWIDTH_HZ*((double)update_period_us)/1e6;
64     m_dll_coeff_b = bw_rel * (DLL_SQRT2 * DLL_2PI);
65     m_dll_coeff_c = bw_rel * bw_rel * DLL_2PI * DLL_2PI;
66
67 }
68
69 CycleTimerHelper::CycleTimerHelper(Ieee1394Service &parent, unsigned int update_period_us, bool rt, int prio)
70     : m_Parent ( parent )
71     , m_ticks_per_update ( ((uint64_t)TICKS_PER_SECOND) * ((uint64_t)update_period_us) / 1000000ULL )
72     , m_usecs_per_update ( update_period_us )
73     , m_avg_wakeup_delay ( 0.0 )
74     , m_dll_e2 ( 0.0 )
75     , m_current_time_usecs ( 0 )
76     , m_next_time_usecs ( 0 )
77     , m_current_time_ticks ( 0 )
78     , m_next_time_ticks ( 0 )
79     , m_first_run ( true )
80     , m_sleep_until ( 0 )
81     , m_cycle_timer_prev ( 0 )
82     , m_cycle_timer_ticks_prev ( 0 )
83     , m_current_shadow_idx ( 0 )
84     , m_Thread ( NULL )
85     , m_realtime ( rt )
86     , m_priority ( prio )
87     , m_update_lock( new Util::PosixMutex("CTRUPD") )
88     , m_busreset_functor ( NULL)
89     , m_unhandled_busreset ( false )
90 {
91     debugOutput( DEBUG_LEVEL_VERBOSE, "Create %p...\n", this);
92
93     double bw_rel = IEEE1394SERVICE_CYCLETIMER_DLL_BANDWIDTH_HZ*((double)update_period_us)/1e6;
94     m_dll_coeff_b = bw_rel * (DLL_SQRT2 * DLL_2PI);
95     m_dll_coeff_c = bw_rel * bw_rel * DLL_2PI * DLL_2PI;
96 }
97
98 CycleTimerHelper::~CycleTimerHelper()
99 {
100     if (m_Thread) {
101         m_Thread->Stop();
102         delete m_Thread;
103     }
104
105     // unregister the bus reset handler
106     if(m_busreset_functor) {
107         m_Parent.remBusResetHandler( m_busreset_functor );
108         delete m_busreset_functor;
109     }
110     delete m_update_lock;
111 }
112
113 bool
114 CycleTimerHelper::Start()
115 {
116     debugOutput( DEBUG_LEVEL_VERBOSE, "Start %p...\n", this);
117
118     if(!initValues()) {
119         debugFatal("(%p) Could not init values\n", this);
120         return false;
121     }
122
123     m_Thread = new Util::PosixThread(this, "CTRHLP", m_realtime, m_priority,
124                                      PTHREAD_CANCEL_DEFERRED);
125     if(!m_Thread) {
126         debugFatal("No thread\n");
127         return false;
128     }
129     // register the thread with the RT watchdog
130     Util::Watchdog *watchdog = m_Parent.getWatchdog();
131     if(watchdog) {
132         if(!watchdog->registerThread(m_Thread)) {
133             debugWarning("could not register update thread with watchdog\n");
134         }
135     } else {
136         debugWarning("could not find valid watchdog\n");
137     }
138    
139     if (m_Thread->Start() != 0) {
140         debugFatal("Could not start update thread\n");
141         return false;
142     }
143     return true;
144 }
145
146 bool
147 CycleTimerHelper::initValues()
148 {
149     debugOutput( DEBUG_LEVEL_VERBOSE, "(%p) Init values...\n", this );
150     Util::MutexLockHelper lock(*m_update_lock);
151
152     // initialize the 'prev ctr' values
153     uint64_t local_time;
154     int maxtries2 = 10;
155     do {
156         debugOutput( DEBUG_LEVEL_VERBOSE, "Read CTR...\n" );
157         if(!m_Parent.readCycleTimerReg(&m_cycle_timer_prev, &local_time)) {
158             debugError("Could not read cycle timer register\n");
159             return false;
160         }
161         if (m_cycle_timer_prev == 0) {
162             debugOutput(DEBUG_LEVEL_VERBOSE,
163                         "Bogus CTR: %08X on try %02d\n",
164                         m_cycle_timer_prev, maxtries2);
165         }
166         debugOutput( DEBUG_LEVEL_VERBOSE, " read : CTR: %11lu, local: %17llu\n",
167                             m_cycle_timer_prev, local_time);
168         debugOutput(DEBUG_LEVEL_VERBOSE,
169                            "  ctr   : 0x%08X %11llu (%03us %04ucy %04uticks)\n",
170                            (uint32_t)m_cycle_timer_prev, (uint64_t)CYCLE_TIMER_TO_TICKS(m_cycle_timer_prev),
171                            (unsigned int)CYCLE_TIMER_GET_SECS( m_cycle_timer_prev ),
172                            (unsigned int)CYCLE_TIMER_GET_CYCLES( m_cycle_timer_prev ),
173                            (unsigned int)CYCLE_TIMER_GET_OFFSET( m_cycle_timer_prev ) );
174        
175     } while (m_cycle_timer_prev == 0 && maxtries2--);
176     m_cycle_timer_ticks_prev = CYCLE_TIMER_TO_TICKS(m_cycle_timer_prev);
177
178 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
179     debugOutput( DEBUG_LEVEL_VERBOSE, "requesting DLL re-init...\n" );
180     Util::SystemTimeSource::SleepUsecRelative(1000); // some time to settle
181     if(!initDLL()) {
182         debugError("(%p) Could not init DLL\n", this);
183         return false;
184     }
185     // make the DLL re-init itself as if it were started up
186     m_first_run = true;
187 #endif
188     debugOutput( DEBUG_LEVEL_VERBOSE, "ready...\n" );
189     return true;
190 }
191
192 bool
193 CycleTimerHelper::Init()
194 {
195     debugOutput( DEBUG_LEVEL_VERBOSE, "Initialize %p...\n", this);
196
197     // register a bus reset handler
198     m_busreset_functor = new Util::MemberFunctor0< CycleTimerHelper*,
199                 void (CycleTimerHelper::*)() >
200                 ( this, &CycleTimerHelper::busresetHandler, false );
201     if ( !m_busreset_functor ) {
202         debugFatal( "(%p) Could not create busreset handler\n", this );
203         return false;
204     }
205     m_Parent.addBusResetHandler( m_busreset_functor );
206
207     #ifdef DEBUG
208     m_last_loop_entry = 0;
209     m_successive_short_loops = 0;
210     #endif
211
212     return true;
213 }
214
215 void
216 CycleTimerHelper::busresetHandler()
217 {
218     debugOutput( DEBUG_LEVEL_VERBOSE, "Bus reset...\n" );
219     m_unhandled_busreset = true;
220     // whenever a bus reset occurs, the root node can change,
221     // and the CTR timer can be reset. We should hence reinit
222     // the DLL
223     if(!initValues()) {
224         debugError("(%p) Could not re-init values\n", this);
225     }
226     m_unhandled_busreset = false;
227 }
228
229 bool
230 CycleTimerHelper::setThreadParameters(bool rt, int priority) {
231     debugOutput( DEBUG_LEVEL_VERBOSE, "(%p) switch to: (rt=%d, prio=%d)...\n", this, rt, priority);
232     if (priority > THREAD_MAX_RTPRIO) priority = THREAD_MAX_RTPRIO; // cap the priority
233     m_realtime = rt;
234     m_priority = priority;
235
236 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
237     if (m_Thread) {
238         if (m_realtime) {
239             m_Thread->AcquireRealTime(m_priority);
240         } else {
241             m_Thread->DropRealTime();
242         }
243     }
244 #endif
245
246     return true;
247 }
248
249 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
250 float
251 CycleTimerHelper::getRate()
252 {
253     float rate = (float)(diffTicks((uint64_t)m_next_time_ticks, (uint64_t)m_current_time_ticks));
254     rate /= (float)(m_next_time_usecs - m_current_time_usecs);
255     return rate;
256 }
257
258 float
259 CycleTimerHelper::getNominalRate()
260 {
261     float rate = ((double)TICKS_PER_SECOND) / 1000000.0;
262     return rate;
263 }
264
265 /*
266  * call with lock held
267  */
268 bool
269 CycleTimerHelper::initDLL() {
270     uint32_t cycle_timer;
271     uint64_t local_time;
272     uint64_t cycle_timer_ticks;
273
274     double bw_rel = m_dll_coeff_b / (DLL_SQRT2 * DLL_2PI);
275     double bw_abs = bw_rel / (m_usecs_per_update / 1e6);
276     if (bw_rel > 0.5) {
277         double bw_max = 0.5 / (m_usecs_per_update / 1e6);
278         debugWarning("Specified DLL bandwidth too high (%f > %f), reducing to max."
279                      " Increase the DLL update rate to increase the max DLL bandwidth\n", bw_abs, bw_max);
280
281         bw_rel = 0.49;
282         bw_abs = bw_rel / (m_usecs_per_update / 1e6);
283         m_dll_coeff_b = bw_rel * (DLL_SQRT2 * DLL_2PI);
284         m_dll_coeff_c = bw_rel * bw_rel * DLL_2PI * DLL_2PI;
285     }
286
287     if(!readCycleTimerWithRetry(&cycle_timer, &local_time, 10)) {
288         debugError("Could not read cycle timer register\n");
289         return false;
290     }
291     cycle_timer_ticks = CYCLE_TIMER_TO_TICKS(cycle_timer);
292
293     debugOutputExtreme( DEBUG_LEVEL_VERY_VERBOSE, " read : CTR: %11lu, local: %17llu\n",
294                         cycle_timer, local_time);
295     debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
296                        "  ctr   : 0x%08X %11llu (%03us %04ucy %04uticks)\n",
297                        (uint32_t)cycle_timer, (uint64_t)cycle_timer_ticks,
298                        (unsigned int)TICKS_TO_SECS( (uint64_t)cycle_timer_ticks ),
299                        (unsigned int)TICKS_TO_CYCLES( (uint64_t)cycle_timer_ticks ),
300                        (unsigned int)TICKS_TO_OFFSET( (uint64_t)cycle_timer_ticks ) );
301
302     m_sleep_until = local_time + m_usecs_per_update;
303     m_dll_e2 = m_ticks_per_update;
304     m_current_time_usecs = local_time;
305     m_next_time_usecs = m_current_time_usecs + m_usecs_per_update;
306     m_current_time_ticks = CYCLE_TIMER_TO_TICKS( cycle_timer );
307     m_next_time_ticks = addTicks( (uint64_t)m_current_time_ticks, (uint64_t)m_dll_e2);
308     debugOutput(DEBUG_LEVEL_VERBOSE, " (%p) First run\n", this);
309     debugOutput(DEBUG_LEVEL_VERBOSE, "  DLL bandwidth: %f Hz (rel: %f)\n",
310                 bw_abs, bw_rel);
311     debugOutput(DEBUG_LEVEL_VERBOSE,
312                 "  usecs/update: %lu, ticks/update: %lu, m_dll_e2: %f\n",
313                 m_usecs_per_update, m_ticks_per_update, m_dll_e2);
314     debugOutput(DEBUG_LEVEL_VERBOSE,
315                 "  usecs current: %f, next: %f\n",
316                 m_current_time_usecs, m_next_time_usecs);
317     debugOutput(DEBUG_LEVEL_VERBOSE,
318                 "  ticks current: %f, next: %f\n",
319                 m_current_time_ticks, m_next_time_ticks);
320     return true;
321 }
322
323 bool
324 CycleTimerHelper::Execute()
325 {
326     debugOutput( DEBUG_LEVEL_ULTRA_VERBOSE, "Execute %p...\n", this);
327
328     #ifdef DEBUG
329     uint64_t now = m_Parent.getCurrentTimeAsUsecs();
330     int diff = now - m_last_loop_entry;
331     if(diff < 100) {
332         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
333                         "(%p) short loop detected (%d usec), cnt: %d\n",
334                         this, diff, m_successive_short_loops);
335         m_successive_short_loops++;
336         if(m_successive_short_loops > 100) {
337             debugError("Shutting down runaway thread\n");
338             return false;
339         }
340     } else {
341         // reset the counter
342         m_successive_short_loops = 0;
343     }
344     m_last_loop_entry = now;
345     #endif
346
347     if (!m_first_run) {
348         // wait for the next update period
349         //#if DEBUG_EXTREME_ENABLE
350         #ifdef DEBUG
351         ffado_microsecs_t now = Util::SystemTimeSource::getCurrentTimeAsUsecs();
352         int sleep_time = m_sleep_until - now;
353         debugOutput( DEBUG_LEVEL_ULTRA_VERBOSE, "(%p) Sleep until %lld/%f (now: %lld, diff=%d) ...\n",
354                     this, m_sleep_until, m_next_time_usecs, now, sleep_time);
355         #endif
356         Util::SystemTimeSource::SleepUsecAbsolute(m_sleep_until);
357         debugOutput( DEBUG_LEVEL_ULTRA_VERBOSE, " (%p) back...\n", this);
358     }
359
360     uint32_t cycle_timer;
361     uint64_t local_time;
362     int64_t usecs_late;
363     int ntries=10;
364     uint64_t cycle_timer_ticks;
365     int64_t err_ticks;
366     bool not_good;
367
368     // if the difference between the predicted value at readout time and the
369     // actual value seems to be too large, retry reading the cycle timer
370     // some host controllers return bogus values on some reads
371     // (looks like a non-atomic update of the register)
372     do {
373         debugOutput( DEBUG_LEVEL_ULTRA_VERBOSE, "(%p) reading cycle timer register...\n", this);
374         if(!readCycleTimerWithRetry(&cycle_timer, &local_time, 10)) {
375             debugError("Could not read cycle timer register\n");
376             return false;
377         }
378         usecs_late = local_time - m_sleep_until;
379         cycle_timer_ticks = CYCLE_TIMER_TO_TICKS(cycle_timer);
380
381         // calculate the CTR_TICKS we expect to read at "local_time"
382         // then calculate the difference with what we actually read,
383         // taking wraparound into account. If these deviate too much
384         // from eachother then read the register again (bogus read).
385         int64_t expected_ticks = getCycleTimerTicks(local_time);
386         err_ticks = diffTicks(cycle_timer_ticks, expected_ticks);
387
388         // check for unrealistic CTR reads (NEC controller does that sometimes)
389         not_good = (-err_ticks > 1*TICKS_PER_CYCLE || err_ticks > 1*TICKS_PER_CYCLE);
390         if(not_good) {
391             debugOutput(DEBUG_LEVEL_VERBOSE,
392                         "(%p) have to retry CTR read, diff unrealistic: diff: %lld, max: +/- %ld (try: %d) %lld\n",
393                         this, err_ticks, 1*TICKS_PER_CYCLE, ntries, expected_ticks);
394             // sleep half a cycle to make sure the hardware moved on
395             Util::SystemTimeSource::SleepUsecRelative(USECS_PER_CYCLE);
396         }
397
398     } while(not_good && --ntries && !m_first_run && !m_unhandled_busreset);
399
400     // grab the lock after sleeping, otherwise we can't be interrupted by
401     // the busreset thread (lower prio)
402     // also grab it after reading the CTR register such that the jitter between
403     // wakeup and read is as small as possible
404     Util::MutexLockHelper lock(*m_update_lock);
405
406     // the difference between the measured and the expected time
407     int64_t diff_ticks = diffTicks(cycle_timer_ticks, (int64_t)m_next_time_ticks);
408
409     // // simulate a random scheduling delay between (0-10ms)
410     // ffado_microsecs_t tmp = Util::SystemTimeSource::SleepUsecRandom(10000);
411     // debugOutput( DEBUG_LEVEL_VERBOSE, " (%p) random sleep of %llu usecs...\n", this, tmp);
412
413     if(m_unhandled_busreset) {
414         debugOutput(DEBUG_LEVEL_VERBOSE,
415                     "(%p) Skipping DLL update due to unhandled busreset\n", this);
416         m_sleep_until += m_usecs_per_update;
417         // keep the thread running
418         return true;
419     }
420
421     debugOutputExtreme( DEBUG_LEVEL_ULTRA_VERBOSE, " read : CTR: %11lu, local: %17llu\n",
422                         cycle_timer, local_time);
423     debugOutputExtreme(DEBUG_LEVEL_ULTRA_VERBOSE,
424                        "  ctr   : 0x%08X %11llu (%03us %04ucy %04uticks)\n",
425                        (uint32_t)cycle_timer, (uint64_t)cycle_timer_ticks,
426                        (unsigned int)TICKS_TO_SECS( (uint64_t)cycle_timer_ticks ),
427                        (unsigned int)TICKS_TO_CYCLES( (uint64_t)cycle_timer_ticks ),
428                        (unsigned int)TICKS_TO_OFFSET( (uint64_t)cycle_timer_ticks ) );
429
430     if (m_first_run) {
431         if(!initDLL()) {
432             debugError("(%p) Could not init DLL\n", this);
433             return false;
434         }
435         m_first_run = false;
436     } else if (diff_ticks > m_ticks_per_update * 20) {
437         debugOutput(DEBUG_LEVEL_VERBOSE,
438                     "re-init dll due to too large tick diff: %lld >> %f\n",
439                     diff_ticks, (float)(m_ticks_per_update * 20));
440         if(!initDLL()) {
441             debugError("(%p) Could not init DLL\n", this);
442             return false;
443         }
444     } else {
445         // calculate next sleep time
446         m_sleep_until += m_usecs_per_update;
447
448         // correct for the latency between the wakeup and the actual CTR
449         // read. The only time we can trust is the time returned by the
450         // CTR read kernel call, since that (should be) atomically read
451         // together with the ctr register itself.
452
453         // if we are usecs_late usecs late
454         // the cycle timer has ticked approx ticks_late ticks too much
455         // if we are woken up early (which shouldn't happen according to POSIX)
456         // the cycle timer has ticked approx -ticks_late too little
457         int64_t ticks_late = (usecs_late * TICKS_PER_SECOND) / 1000000LL;
458         // the corrected difference between predicted and actual ctr
459         // i.e. DLL error signal
460         int64_t diff_ticks_corr;
461         if (ticks_late >= 0) {
462             diff_ticks_corr = diff_ticks - ticks_late;
463             debugOutputExtreme(DEBUG_LEVEL_ULTRA_VERBOSE,
464                                "diff_ticks_corr=%lld, diff_ticks = %lld, ticks_late = %lld\n",
465                                diff_ticks_corr, diff_ticks, ticks_late);
466         } else {
467             debugError("Early wakeup, should not happen!\n");
468             // recover
469             diff_ticks_corr = diff_ticks + ticks_late;
470         }
471
472         #ifdef DEBUG
473         // makes no sense if not running realtime
474         if(m_realtime && usecs_late > 1000) {
475             debugOutput(DEBUG_LEVEL_VERBOSE, "Rather late wakeup: %lld usecs\n", usecs_late);
476         }
477         #endif
478
479         // update the x-axis values
480         m_current_time_ticks = m_next_time_ticks;
481
482         // decide what coefficients to use
483
484         // it should be ok to not do this in tick space
485         // since diff_ticks_corr should not be near wrapping
486         // (otherwise we are out of range. we need a few calls
487         //  w/o wrapping for this to work. That should not be
488         //  an issue as long as the update interval is smaller
489         //  than the wrapping interval.)
490         // and coeff_b < 1, hence tmp is not near wrapping
491
492         double diff_ticks_corr_d =  (double)diff_ticks_corr;
493         double step_ticks = (m_dll_coeff_b * diff_ticks_corr_d);
494         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
495                            "diff_ticks_corr=%f, step_ticks=%f\n",
496                            diff_ticks_corr_d, step_ticks);
497
498         // the same goes for m_dll_e2, which should be approx equal
499         // to the ticks/usec rate (= 24.576) hence also not near
500         // wrapping
501         step_ticks += m_dll_e2;
502         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
503                            "add %f ticks to step_ticks => step_ticks=%f\n",
504                            m_dll_e2, step_ticks);
505
506         // it can't be that we have to update to a value in the past
507         if(step_ticks < 0) {
508             debugError("negative step: %f! (correcting to nominal)\n", step_ticks);
509             // recover to an estimated value
510             step_ticks = (double)m_ticks_per_update;
511         }
512
513         if(step_ticks > TICKS_PER_SECOND) {
514             debugWarning("rather large step: %f ticks (> 1sec)\n", step_ticks);
515         }
516
517         // now add the step ticks with wrapping.
518         m_next_time_ticks = (double)(addTicks((uint64_t)m_current_time_ticks, (uint64_t)step_ticks));
519
520         // update the DLL state
521         m_dll_e2 += m_dll_coeff_c * diff_ticks_corr_d;
522
523         // update the y-axis values
524         m_current_time_usecs = m_next_time_usecs;
525         m_next_time_usecs += m_usecs_per_update;
526
527         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
528                            " usecs: current: %f next: %f usecs_late=%lld ticks_late=%lld\n",
529                            m_current_time_usecs, m_next_time_usecs, usecs_late, ticks_late);
530         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
531                            " ticks: current: %f next: %f diff=%lld\n",
532                            m_current_time_ticks, m_next_time_ticks, diff_ticks);
533         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
534                            " ticks: current: %011llu (%03us %04ucy %04uticks)\n",
535                            (uint64_t)m_current_time_ticks,
536                            (unsigned int)TICKS_TO_SECS( (uint64_t)m_current_time_ticks ),
537                            (unsigned int)TICKS_TO_CYCLES( (uint64_t)m_current_time_ticks ),
538                            (unsigned int)TICKS_TO_OFFSET( (uint64_t)m_current_time_ticks ) );
539         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
540                            " ticks: next   : %011llu (%03us %04ucy %04uticks)\n",
541                            (uint64_t)m_next_time_ticks,
542                            (unsigned int)TICKS_TO_SECS( (uint64_t)m_next_time_ticks ),
543                            (unsigned int)TICKS_TO_CYCLES( (uint64_t)m_next_time_ticks ),
544                            (unsigned int)TICKS_TO_OFFSET( (uint64_t)m_next_time_ticks ) );
545
546         debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE,
547                            " state: local: %11llu, dll_e2: %f, rate: %f\n",
548                            local_time, m_dll_e2, getRate());
549     }
550
551     // prepare the new compute vars
552     struct compute_vars new_vars;
553     new_vars.ticks = (uint64_t)(m_current_time_ticks);
554     new_vars.usecs = (uint64_t)m_current_time_usecs;
555     new_vars.rate = getRate();
556
557     // get the next index
558     unsigned int next_idx = (m_current_shadow_idx + 1) % CTRHELPER_NB_SHADOW_VARS;
559
560     // update the next index position
561     m_shadow_vars[next_idx] = new_vars;
562
563     // then we can update the current index
564     m_current_shadow_idx = next_idx;
565
566 #ifdef DEBUG
567     // do some verification
568     // we re-read a valid ctr timestamp
569     // then we use the attached system time to calculate
570     // the DLL generated timestamp and we check what the
571     // difference is
572
573     if(!readCycleTimerWithRetry(&cycle_timer, &local_time, 10)) {
574         debugError("Could not read cycle timer register (verify)\n");
575         return true; // true since this is a check only
576     }
577     cycle_timer_ticks = CYCLE_TIMER_TO_TICKS(cycle_timer);
578
579     // only check when successful
580     int64_t time_diff = local_time - new_vars.usecs;
581     double y_step_in_ticks = ((double)time_diff) * new_vars.rate;
582     int64_t y_step_in_ticks_int = (int64_t)y_step_in_ticks;
583     uint64_t offset_in_ticks_int = new_vars.ticks;
584     uint32_t dll_time;
585     if (y_step_in_ticks_int > 0) {
586         dll_time = addTicks(offset_in_ticks_int, y_step_in_ticks_int);
587     } else {
588         dll_time = substractTicks(offset_in_ticks_int, -y_step_in_ticks_int);
589     }
590     int32_t ctr_diff = cycle_timer_ticks-dll_time;
591     debugOutput(DEBUG_LEVEL_ULTRA_VERBOSE, "(%p) CTR DIFF: HW %010llu - DLL %010lu = %010ld (%s)\n",
592                 this, cycle_timer_ticks, dll_time, ctr_diff, (ctr_diff>0?"lag":"lead"));
593 #endif
594
595     return true;
596 }
597
598 uint32_t
599 CycleTimerHelper::getCycleTimerTicks()
600 {
601     uint64_t now = m_Parent.getCurrentTimeAsUsecs();
602     return getCycleTimerTicks(now);
603 }
604
605 uint32_t
606 CycleTimerHelper::getCycleTimerTicks(uint64_t now)
607 {
608     uint32_t retval;
609     struct compute_vars *my_vars;
610
611     // get pointer and copy the contents
612     // no locking should be needed since we have more than one
613     // of these vars available, and our use will always be finished before
614     // m_current_shadow_idx changes since this thread's priority should
615     // be higher than the one of the writer thread. Even if not, we only have to ensure
616     // that the used dataset is consistent. We can use an older dataset if it's consistent
617     // since it will also provide a fairly decent extrapolation.
618     my_vars = m_shadow_vars + m_current_shadow_idx;
619
620     int64_t time_diff = now - my_vars->usecs;
621     double y_step_in_ticks = ((double)time_diff) * my_vars->rate;
622     int64_t y_step_in_ticks_int = (int64_t)y_step_in_ticks;
623     uint64_t offset_in_ticks_int = my_vars->ticks;
624
625     if (y_step_in_ticks_int > 0) {
626         retval = addTicks(offset_in_ticks_int, y_step_in_ticks_int);
627 /*        debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE, "y_step_in_ticks_int > 0: %lld, time_diff: %f, rate: %f, retval: %lu\n",
628                     y_step_in_ticks_int, time_diff, my_vars.rate, retval);*/
629     } else {
630         retval = substractTicks(offset_in_ticks_int, -y_step_in_ticks_int);
631
632         // this can happen if the update thread was woken up earlier than it should have been
633 /*        debugOutputExtreme(DEBUG_LEVEL_VERY_VERBOSE, "y_step_in_ticks_int <= 0: %lld, time_diff: %f, rate: %f, retval: %lu\n",
634                     y_step_in_ticks_int, time_diff, my_vars.rate, retval);*/
635     }
636
637     return retval;
638 }
639
640 uint32_t
641 CycleTimerHelper::getCycleTimer()
642 {
643     uint64_t now = m_Parent.getCurrentTimeAsUsecs();
644     return getCycleTimer(now);
645 }
646
647 uint32_t
648 CycleTimerHelper::getCycleTimer(uint64_t now)
649 {
650     uint32_t ticks = getCycleTimerTicks(now);
651     uint32_t result = TICKS_TO_CYCLE_TIMER(ticks);
652 #ifdef DEBUG
653     if(CYCLE_TIMER_TO_TICKS(result) != ticks) {
654         debugWarning("Bad ctr conversion");
655     }
656 #endif
657     return result;
658 }
659
660 uint64_t
661 CycleTimerHelper::getSystemTimeForCycleTimerTicks(uint32_t ticks)
662 {
663     uint64_t retval;
664     struct compute_vars *my_vars;
665
666     // get pointer and copy the contents
667     // no locking should be needed since we have more than one
668     // of these vars available, and our use will always be finished before
669     // m_current_shadow_idx changes since this thread's priority should
670     // be higher than the one of the writer thread. Even if not, we only have to ensure
671     // that the used dataset is consistent. We can use an older dataset if it's consistent
672     // since it will also provide a fairly decent extrapolation.
673     my_vars = m_shadow_vars + m_current_shadow_idx;
674
675     // the number of ticks the request is ahead of the current CTR position
676     int64_t ticks_diff = diffTicks(ticks, my_vars->ticks);
677     // to how much time does this correspond?
678     double x_step_in_usec = ((double)ticks_diff) / my_vars->rate;
679     int64_t x_step_in_usec_int = (int64_t)x_step_in_usec;
680     retval = my_vars->usecs + x_step_in_usec_int;
681
682     return retval;
683 }
684
685 uint64_t
686 CycleTimerHelper::getSystemTimeForCycleTimer(uint32_t ctr)
687 {
688     uint32_t ticks = CYCLE_TIMER_TO_TICKS(ctr);
689     return getSystemTimeForCycleTimerTicks(ticks);
690 }
691
692 #else
693
694 float
695 CycleTimerHelper::getRate()
696 {
697     return getNominalRate();
698 }
699
700 float
701 CycleTimerHelper::getNominalRate()
702 {
703     float rate = ((double)TICKS_PER_SECOND) / 1000000.0;
704     return rate;
705 }
706
707 bool
708 CycleTimerHelper::Execute()
709 {
710     usleep(1000*1000);
711     return true;
712 }
713
714 uint32_t
715 CycleTimerHelper::getCycleTimerTicks()
716 {
717     return CYCLE_TIMER_TO_TICKS(getCycleTimer());
718 }
719
720 uint32_t
721 CycleTimerHelper::getCycleTimerTicks(uint64_t now)
722 {
723     debugWarning("untested code\n");
724     #warning Untested code
725     uint32_t cycle_timer;
726     uint64_t local_time;
727     readCycleTimerWithRetry(&cycle_timer, &local_time, 10);
728     int64_t ticks = CYCLE_TIMER_TO_TICKS(cycle_timer);
729
730     int delta_t = now - local_time; // how far ahead is the request?
731     ticks += delta_t * getRate(); // add ticks
732     if (ticks >= TICKS_PER_SECOND * 128) ticks -= TICKS_PER_SECOND * 128;
733     else if (ticks < 0) ticks += TICKS_PER_SECOND * 128;
734     return ticks;
735 }
736
737 uint32_t
738 CycleTimerHelper::getCycleTimer()
739 {
740     uint32_t cycle_timer;
741     uint64_t local_time;
742     readCycleTimerWithRetry(&cycle_timer, &local_time, 10);
743     return cycle_timer;
744 }
745
746 uint32_t
747 CycleTimerHelper::getCycleTimer(uint64_t now)
748 {
749     return TICKS_TO_CYCLE_TIMER(getCycleTimerTicks(now));
750 }
751
752 uint64_t
753 CycleTimerHelper::getSystemTimeForCycleTimerTicks(uint32_t ticks)
754 {
755     debugWarning("not implemented!\n");
756     return 0;
757 }
758
759 uint64_t
760 CycleTimerHelper::getSystemTimeForCycleTimer(uint32_t ctr)
761 {
762     uint32_t ticks = CYCLE_TIMER_TO_TICKS(ctr);
763     return getSystemTimeForCycleTimerTicks(ticks);
764 }
765
766 #endif
767
768 bool
769 CycleTimerHelper::readCycleTimerWithRetry(uint32_t *cycle_timer, uint64_t *local_time, int ntries)
770 {
771     bool good=false;
772     int maxtries = ntries;
773
774     do {
775         // the ctr read can return 0 sometimes. if that happens, reread the ctr.
776         int maxtries2=ntries;
777         do {
778             if(!m_Parent.readCycleTimerReg(cycle_timer, local_time)) {
779                 debugError("Could not read cycle timer register\n");
780                 return false;
781             }
782             if (*cycle_timer == 0) {
783                 debugOutput(DEBUG_LEVEL_VERBOSE,
784                            "Bogus CTR: %08X on try %02d\n",
785                            *cycle_timer, maxtries2);
786             }
787         } while (*cycle_timer == 0 && maxtries2--);
788        
789         // catch bogus ctr reads (can happen)
790         uint64_t cycle_timer_ticks = CYCLE_TIMER_TO_TICKS(*cycle_timer);
791    
792         if (diffTicks(cycle_timer_ticks, m_cycle_timer_ticks_prev) < 0) {
793             debugOutput( DEBUG_LEVEL_VERY_VERBOSE,
794                         "non-monotonic CTR (try %02d): %llu -> %llu\n",
795                         maxtries, m_cycle_timer_ticks_prev, cycle_timer_ticks);
796             debugOutput( DEBUG_LEVEL_VERY_VERBOSE,
797                         "                            : %08X -> %08X\n",
798                         m_cycle_timer_prev, *cycle_timer);
799             debugOutput( DEBUG_LEVEL_VERY_VERBOSE,
800                         " current: %011llu (%03us %04ucy %04uticks)\n",
801                         cycle_timer_ticks,
802                         (unsigned int)TICKS_TO_SECS( cycle_timer_ticks ),
803                         (unsigned int)TICKS_TO_CYCLES( cycle_timer_ticks ),
804                         (unsigned int)TICKS_TO_OFFSET( cycle_timer_ticks ) );
805             debugOutput( DEBUG_LEVEL_VERY_VERBOSE,
806                         " prev   : %011llu (%03us %04ucy %04uticks)\n",
807                         m_cycle_timer_ticks_prev,
808                         (unsigned int)TICKS_TO_SECS( m_cycle_timer_ticks_prev ),
809                         (unsigned int)TICKS_TO_CYCLES( m_cycle_timer_ticks_prev ),
810                         (unsigned int)TICKS_TO_OFFSET( m_cycle_timer_ticks_prev ) );
811         } else {
812             good = true;
813             m_cycle_timer_prev = *cycle_timer;
814             m_cycle_timer_ticks_prev = cycle_timer_ticks;
815         }
816     } while (!good && maxtries--);
817     return true;
818 }
819
820 void
821 CycleTimerHelper::setVerboseLevel(int l)
822 {
823     setDebugLevel(l);
824 }
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