root/trunk/libffado/src/libieee1394/CycleTimerHelper.cpp

Revision 863, 11.1 kB (checked in by ppalmers, 13 years ago)

fix cycle timer DLL code

Line 
1 /*
2  * Copyright (C) 2005-2007 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 3 of the License, or
12  * (at your option) any later version.
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
30 #define DLL_BANDWIDTH (0.1)
31 #define DLL_PI        (3.141592653589793238)
32 #define DLL_SQRT2     (1.414213562373095049)
33 #define DLL_OMEGA     (2.0*DLL_PI*DLL_BANDWIDTH)
34 #define DLL_COEFF_B   (DLL_SQRT2 * DLL_OMEGA)
35 #define DLL_COEFF_C   (DLL_OMEGA * DLL_OMEGA)
36
37 #define OFFSET_AVERAGE_COEFF 0.01
38 /*
39 #define ENTER_CRITICAL_SECTION { \
40     if (pthread_mutex_trylock(&m_compute_vars_lock) == EBUSY) { \
41         debugWarning(" (%p) lock clash\n", this); \
42         ENTER_CRITICAL_SECTION; \
43     } \
44     }
45 */
46 #define ENTER_CRITICAL_SECTION { \
47     pthread_mutex_lock(&m_compute_vars_lock); \
48     }
49 #define EXIT_CRITICAL_SECTION { \
50     pthread_mutex_unlock(&m_compute_vars_lock); \
51     }
52
53 IMPL_DEBUG_MODULE( CycleTimerHelper, CycleTimerHelper, DEBUG_LEVEL_NORMAL );
54
55 CycleTimerHelper::CycleTimerHelper(Ieee1394Service &parent, unsigned int update_period_us)
56     : m_Parent ( parent )
57     , m_ticks_per_update ( ((uint64_t)TICKS_PER_SECOND) * ((uint64_t)update_period_us) / 1000000ULL )
58     , m_usecs_per_update ( update_period_us )
59     , m_avg_wakeup_delay ( 0.0 )
60     , m_dll_e2 ( 0.0 )
61     , m_current_time_usecs ( 0 )
62     , m_next_time_usecs ( 0 )
63     , m_current_time_ticks ( 0 )
64     , m_next_time_ticks ( 0 )
65     , m_first_run ( true )
66     , m_sleep_until ( 0 )
67     , m_Thread ( NULL )
68     , m_realtime ( false )
69     , m_priority ( 0 )
70 {
71     debugOutput( DEBUG_LEVEL_VERBOSE, "Create %p...\n", this);
72 }
73
74 CycleTimerHelper::CycleTimerHelper(Ieee1394Service &parent, unsigned int update_period_us, bool rt, int prio)
75     : m_Parent ( parent )
76     , m_ticks_per_update ( ((uint64_t)TICKS_PER_SECOND) * ((uint64_t)update_period_us) / 1000000ULL )
77     , m_usecs_per_update ( update_period_us )
78     , m_avg_wakeup_delay ( 0.0 )
79     , m_dll_e2 ( 0.0 )
80     , m_current_time_usecs ( 0 )
81     , m_next_time_usecs ( 0 )
82     , m_current_time_ticks ( 0 )
83     , m_next_time_ticks ( 0 )
84     , m_first_run ( true )
85     , m_sleep_until ( 0 )
86     , m_Thread ( NULL )
87     , m_realtime ( rt )
88     , m_priority ( prio )
89 {
90     debugOutput( DEBUG_LEVEL_VERBOSE, "Create %p...\n", this);
91 }
92
93 CycleTimerHelper::~CycleTimerHelper()
94 {
95     if (m_Thread) {
96         m_Thread->Stop();
97         delete m_Thread;
98     }
99 }
100
101 bool
102 CycleTimerHelper::Start()
103 {
104     debugOutput( DEBUG_LEVEL_VERBOSE, "Start %p...\n", this);
105 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
106     m_Thread = new Util::PosixThread(this, m_realtime, m_priority,
107                                      PTHREAD_CANCEL_DEFERRED);
108     if(!m_Thread) {
109         debugFatal("No thread\n");
110         return false;
111     }
112     if (m_Thread->Start() != 0) {
113         debugFatal("Could not start update thread\n");
114         return false;
115     }
116 #endif
117     return true;
118 }
119
120 bool
121 CycleTimerHelper::Init()
122 {
123     debugOutput( DEBUG_LEVEL_VERBOSE, "Initialize %p...\n", this);
124     pthread_mutex_init(&m_compute_vars_lock, NULL);
125     return true;
126 }
127
128 bool
129 CycleTimerHelper::setThreadParameters(bool rt, int priority) {
130     debugOutput( DEBUG_LEVEL_VERBOSE, "(%p) switch to: (rt=%d, prio=%d)...\n", this, rt, priority);
131     if (priority > THREAD_MAX_RTPRIO) priority = THREAD_MAX_RTPRIO; // cap the priority
132     m_realtime = rt;
133     m_priority = priority;
134
135 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
136     if (m_Thread) {
137         if (m_realtime) {
138             m_Thread->AcquireRealTime(m_priority);
139         } else {
140             m_Thread->DropRealTime();
141         }
142     }
143 #endif
144
145     return true;
146 }
147
148 #if IEEE1394SERVICE_USE_CYCLETIMER_DLL
149 float
150 CycleTimerHelper::getRate()
151 {
152     float rate = (float)(diffTicks((uint64_t)m_next_time_ticks, (uint64_t)m_current_time_ticks));
153     rate /= (float)(m_next_time_usecs - m_current_time_usecs);
154     return rate;
155 }
156
157 float
158 CycleTimerHelper::getNominalRate()
159 {
160     float rate = ((double)TICKS_PER_SECOND) / 1000000.0;
161     return rate;
162 }
163
164 bool
165 CycleTimerHelper::Execute()
166 {
167     debugOutput( DEBUG_LEVEL_VERY_VERBOSE, "Execute %p...\n", this);
168     if (!m_first_run) {
169         // wait for the next update period
170         ffado_microsecs_t now = m_TimeSource.getCurrentTimeAsUsecs();
171         int sleep_time = m_sleep_until - now;
172         debugOutput( DEBUG_LEVEL_VERY_VERBOSE, "(%p) Sleep until %lld/%f (now: %lld, diff=%d) ...\n",
173                     this, m_sleep_until, m_next_time_usecs, now, sleep_time);
174         m_TimeSource.SleepUsecAbsolute(m_sleep_until);
175         debugOutput( DEBUG_LEVEL_VERY_VERBOSE, " (%p) back...\n", this);
176     }
177
178     uint32_t cycle_timer;
179     uint64_t local_time;
180     if(!m_Parent.readCycleTimerReg(&cycle_timer, &local_time)) {
181         debugError("Could not read cycle timer register\n");
182         return false;
183     }
184     debugOutput( DEBUG_LEVEL_VERY_VERBOSE, " read : CTR: %11lu, local: %17llu\n",
185                     cycle_timer, local_time);
186
187     if (m_first_run) {
188         m_sleep_until = local_time + m_usecs_per_update;
189         m_dll_e2 = m_ticks_per_update;
190         m_current_time_usecs = local_time;
191         m_next_time_usecs = m_current_time_usecs + m_usecs_per_update;
192         m_current_time_ticks = CYCLE_TIMER_TO_TICKS( cycle_timer );
193         m_next_time_ticks = addTicks( (uint64_t)m_current_time_ticks, (uint64_t)m_dll_e2);
194         debugOutput( DEBUG_LEVEL_VERBOSE, " First run\n");
195         debugOutput( DEBUG_LEVEL_VERBOSE, "  usecs/update: %lu, ticks/update: %lu, m_dll_e2: %f\n",
196                                           m_usecs_per_update, m_ticks_per_update, m_dll_e2);
197         debugOutput( DEBUG_LEVEL_VERBOSE, "  usecs current: %f, next: %f\n", m_current_time_usecs, m_next_time_usecs);
198         debugOutput( DEBUG_LEVEL_VERBOSE, "  ticks current: %f, next: %f\n", m_current_time_ticks, m_next_time_ticks);
199         m_first_run = false;
200     } else {
201         m_sleep_until += m_usecs_per_update;
202         uint64_t cycle_timer_ticks = CYCLE_TIMER_TO_TICKS(cycle_timer);
203         double usecs_late = ((double)local_time) - (m_next_time_usecs);
204
205         // update the x-axis values
206         double diff_ticks = diffTicks(cycle_timer_ticks, (int64_t)m_next_time_ticks);
207         m_current_time_ticks = m_next_time_ticks;
208         // do the calculation in 'tick space'
209         int64_t tmp = (uint64_t)(DLL_COEFF_B * diff_ticks);
210         if(m_dll_e2 > 0) {
211             tmp = addTicks(tmp, (uint64_t)m_dll_e2);
212         } else {
213             tmp = substractTicks(tmp, (uint64_t)(-m_dll_e2));
214         }
215         if(tmp < 0) {
216             debugWarning("negative slope: %lld!\n", tmp);
217         }
218         m_next_time_ticks = addTicks((uint64_t)m_current_time_ticks, tmp);
219
220         // it should be ok to not do this in tick space since it's value
221         // is approx equal to the rate, being 24.576 ticks/usec
222         m_dll_e2 += DLL_COEFF_C * diff_ticks;
223
224         // update the y-axis values
225         m_current_time_usecs = m_next_time_usecs;
226         m_next_time_usecs = local_time + m_usecs_per_update;
227
228         debugOutput( DEBUG_LEVEL_VERY_VERBOSE, " usecs: current: %f next: %f usecs_late=%f\n",
229                     m_current_time_usecs, m_next_time_usecs, usecs_late);
230         debugOutput( DEBUG_LEVEL_VERY_VERBOSE, " ticks: current: %f next: %f diff=%f\n",
231                     m_current_time_ticks, m_next_time_ticks, diff_ticks);
232
233         debugOutput( DEBUG_LEVEL_VERY_VERBOSE, " state: local: %11llu, dll_e2: %f, rate: %f\n",
234                     local_time, m_dll_e2, getRate());
235     }
236
237     // FIXME: priority inversion!
238     ENTER_CRITICAL_SECTION;
239     m_current_vars.ticks = (uint64_t)(m_current_time_ticks);// + m_average_offset_ticks);
240     m_current_vars.usecs = (uint64_t)m_current_time_usecs;
241     m_current_vars.rate = getRate();
242     EXIT_CRITICAL_SECTION;
243
244     return true;
245 }
246
247 uint32_t
248 CycleTimerHelper::getCycleTimerTicks()
249 {
250     uint64_t now = m_Parent.getCurrentTimeAsUsecs();
251     return getCycleTimerTicks(now);
252 }
253
254 uint32_t
255 CycleTimerHelper::getCycleTimerTicks(uint64_t now)
256 {
257     uint32_t retval;
258     struct compute_vars my_vars;
259
260     // reduce lock contention
261     ENTER_CRITICAL_SECTION;
262     my_vars = m_current_vars;
263     EXIT_CRITICAL_SECTION;
264
265     int64_t time_diff = now - my_vars.usecs;
266     double y_step_in_ticks = ((double)time_diff) * my_vars.rate;
267     int64_t y_step_in_ticks_int = (int64_t)y_step_in_ticks;
268     uint64_t offset_in_ticks_int = my_vars.ticks;
269
270     if (y_step_in_ticks_int > 0) {
271         retval = addTicks(offset_in_ticks_int, y_step_in_ticks_int);
272         debugOutput(DEBUG_LEVEL_VERY_VERBOSE, "y_step_in_ticks_int > 0: %lld, time_diff: %f, rate: %f, retval: %lu\n",
273                      y_step_in_ticks_int, time_diff, my_vars.rate, retval);
274     } else {
275         retval = substractTicks(offset_in_ticks_int, -y_step_in_ticks_int);
276
277         // this can happen if the update thread was woken up earlier than it should have been
278         debugOutput(DEBUG_LEVEL_VERY_VERBOSE, "y_step_in_ticks_int <= 0: %lld, time_diff: %f, rate: %f, retval: %lu\n",
279                      y_step_in_ticks_int, time_diff, my_vars.rate, retval);
280     }
281
282     return retval;
283 }
284
285 uint32_t
286 CycleTimerHelper::getCycleTimer()
287 {
288     uint64_t now = m_Parent.getCurrentTimeAsUsecs();
289     return getCycleTimer(now);
290 }
291
292 uint32_t
293 CycleTimerHelper::getCycleTimer(uint64_t now)
294 {
295     uint32_t ticks = getCycleTimerTicks(now);
296     uint32_t result = TICKS_TO_CYCLE_TIMER(ticks);
297 #ifdef DEBUG
298     if(CYCLE_TIMER_TO_TICKS(result) != ticks) {
299         debugWarning("Bad ctr conversion");
300     }
301 #endif
302     return result;
303 }
304
305 #else
306
307 float
308 CycleTimerHelper::getRate()
309 {
310     return getNominalRate();
311 }
312
313 float
314 CycleTimerHelper::getNominalRate()
315 {
316     float rate = ((double)TICKS_PER_SECOND) / 1000000.0;
317     return rate;
318 }
319
320 bool
321 CycleTimerHelper::Execute()
322 {
323     usleep(1000*1000);
324     return true;
325 }
326 uint32_t
327 CycleTimerHelper::getCycleTimerTicks()
328 {
329     uint32_t cycle_timer;
330     uint64_t local_time;
331     if(!m_Parent.readCycleTimerReg(&cycle_timer, &local_time)) {
332         debugError("Could not read cycle timer register\n");
333         return 0;
334     }
335     return CYCLE_TIMER_TO_TICKS(cycle_timer);
336 }
337
338 uint32_t
339 CycleTimerHelper::getCycleTimerTicks(uint64_t now)
340 {
341     debugWarning("not implemented!\n");
342     return getCycleTimerTicks();
343 }
344
345 uint32_t
346 CycleTimerHelper::getCycleTimer()
347 {
348     uint32_t cycle_timer;
349     uint64_t local_time;
350     if(!m_Parent.readCycleTimerReg(&cycle_timer, &local_time)) {
351         debugError("Could not read cycle timer register\n");
352         return 0;
353     }
354     return cycle_timer;
355 }
356
357 uint32_t
358 CycleTimerHelper::getCycleTimer(uint64_t now)
359 {
360     debugWarning("not implemented!\n");
361     return getCycleTimer();
362 }
363
364 #endif
365
366 void
367 CycleTimerHelper::setVerboseLevel(int l)
368 {
369     setDebugLevel(l);
370 }
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