libs/ardour/butler.cc

   1 /*
   2     Copyright (C) 1999-2009 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <poll.h>
  24 #include "pbd/error.h"
  25 #include "pbd/pthread_utils.h"
  26 #include "ardour/butler.h"
  27 #include "ardour/crossfade.h"
  28 #include "ardour/io.h"
  29 #include "ardour/midi_diskstream.h"
  30 #include "ardour/session.h"
  31 #include "ardour/track.h"
  32
  33 #include "i18n.h"
  34
  35 using namespace PBD;
  36
  37 static float _read_data_rate;
  38 static float _write_data_rate;
  39
  40 namespace ARDOUR {
  41
  42 Butler::Butler(Session& s)
  43         : SessionHandleRef (s)
  44         , thread(0)
  45         , audio_dstream_buffer_size(0)
  46         , midi_dstream_buffer_size(0)
  47         , pool_trash(16)
  48 {
  49         g_atomic_int_set(&should_do_transport_work, 0);
  50         SessionEvent::pool->set_trash (&pool_trash);
  51 }
  52
  53 Butler::~Butler()
  54 {
  55         terminate_thread ();
  56 }
  57
  58 int
  59 Butler::start_thread()
  60 {
  61         const float rate = (float)_session.frame_rate();
  62
  63         /* size is in Samples, not bytes */
  64         audio_dstream_buffer_size = (uint32_t) floor (Config->get_audio_track_buffer_seconds() * rate);
  65
  66         /* size is in bytes
  67          * XXX: Jack needs to tell us the MIDI buffer size
  68          * (i.e. how many MIDI bytes we might see in a cycle)
  69          */
  70         midi_dstream_buffer_size = (uint32_t) floor (Config->get_midi_track_buffer_seconds() * rate);
  71
  72         MidiDiskstream::set_readahead_frames ((nframes_t)(Config->get_midi_readahead() * rate));
  73
  74         Crossfade::set_buffer_size (audio_dstream_buffer_size);
  75
  76         should_run = false;
  77
  78         if (pipe (request_pipe)) {
  79                 error << string_compose(_("Cannot create transport request signal pipe (%1)"),
  80                                 strerror (errno)) << endmsg;
  81                 return -1;
  82         }
  83
  84         if (fcntl (request_pipe[0], F_SETFL, O_NONBLOCK)) {
  85                 error << string_compose(_("UI: cannot set O_NONBLOCK on butler request pipe (%1)"),
  86                                 strerror (errno)) << endmsg;
  87                 return -1;
  88         }
  89
  90         if (fcntl (request_pipe[1], F_SETFL, O_NONBLOCK)) {
  91                 error << string_compose(_("UI: cannot set O_NONBLOCK on butler request pipe (%1)"),
  92                                 strerror (errno)) << endmsg;
  93                 return -1;
  94         }
  95
  96         if (pthread_create_and_store ("disk butler", &thread, _thread_work, this)) {
  97                 error << _("Session: could not create butler thread") << endmsg;
  98                 return -1;
  99         }
 100
 101         //pthread_detach (thread);
 102
 103         return 0;
 104 }
 105
 106 void
 107 Butler::terminate_thread ()
 108 {
 109         if (thread) {
 110                 void* status;
 111                 const char c = Request::Quit;
 112                 ::write (request_pipe[1], &c, 1);
 113                 pthread_join (thread, &status);
 114         }
 115 }
 116
 117 void *
 118 Butler::_thread_work (void* arg)
 119 {
 120         SessionEvent::create_per_thread_pool ("butler events", 64);
 121         pthread_set_name (X_("butler"));
 122         return ((Butler *) arg)->thread_work ();
 123 }
 124
 125 void *
 126 Butler::thread_work ()
 127 {
 128         uint32_t err = 0;
 129         int32_t bytes;
 130         bool compute_io;
 131         microseconds_t begin, end;
 132
 133         struct pollfd pfd[1];
 134         bool disk_work_outstanding = false;
 135         RouteList::iterator i;
 136
 137         while (true) {
 138                 pfd[0].fd = request_pipe[0];
 139                 pfd[0].events = POLLIN|POLLERR|POLLHUP;
 140
 141                 if (poll (pfd, 1, (disk_work_outstanding ? 0 : -1)) < 0) {
 142
 143                         if (errno == EINTR) {
 144                                 continue;
 145                         }
 146
 147                         error << string_compose (_("poll on butler request pipe failed (%1)"),
 148                                           strerror (errno))
 149                               << endmsg;
 150                         break;
 151                 }
 152
 153                 if (pfd[0].revents & ~POLLIN) {
 154                         error << string_compose (_("Error on butler thread request pipe: fd=%1 err=%2"), pfd[0].fd, pfd[0].revents) << endmsg;
 155                         break;
 156                 }
 157
 158                 if (pfd[0].revents & POLLIN) {
 159
 160                         char req;
 161
 162                         /* empty the pipe of all current requests */
 163
 164                         while (1) {
 165                                 size_t nread = ::read (request_pipe[0], &req, sizeof (req));
 166                                 if (nread == 1) {
 167
 168                                         switch ((Request::Type) req) {
 169
 170                                         case Request::Wake:
 171                                                 break;
 172
 173                                         case Request::Run:
 174                                                 should_run = true;
 175                                                 break;
 176
 177                                         case Request::Pause:
 178                                                 should_run = false;
 179                                                 break;
 180
 181                                         case Request::Quit:
 182                                                 pthread_exit_pbd (0);
 183                                                 /*NOTREACHED*/
 184                                                 break;
 185
 186                                         default:
 187                                                 break;
 188                                         }
 189
 190                                 } else if (nread == 0) {
 191                                         break;
 192                                 } else if (errno == EAGAIN) {
 193                                         break;
 194                                 } else {
 195                                         fatal << _("Error reading from butler request pipe") << endmsg;
 196                                         /*NOTREACHED*/
 197                                 }
 198                         }
 199                 }
 200
 201                 if (transport_work_requested()) {
 202                         _session.butler_transport_work ();
 203                 }
 204
 205                 disk_work_outstanding = false;
 206                 bytes = 0;
 207                 compute_io = true;
 208
 209                 begin = get_microseconds();
 210
 211                 boost::shared_ptr<RouteList> rl = _session.get_routes();
 212
 213 //              for (i = dsl->begin(); i != dsl->end(); ++i) {
 214 //                      cerr << "BEFORE " << (*i)->name() << ": pb = " << (*i)->playback_buffer_load() << " cp = " << (*i)->capture_buffer_load() << endl;
 215 //              }
 216
 217                 for (i = rl->begin(); !transport_work_requested() && should_run && i != rl->end(); ++i) {
 218
 219                         boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 220                         if (!tr) {
 221                                 continue;
 222                         }
 223
 224                         /* don't read inactive tracks */
 225
 226                         boost::shared_ptr<IO> io = tr->input ();
 227
 228                         if (io && !io->active()) {
 229                                 continue;
 230                         }
 231
 232                         switch (tr->do_refill ()) {
 233                         case 0:
 234                                 bytes += tr->read_data_count();
 235                                 break;
 236                         case 1:
 237                                 bytes += tr->read_data_count();
 238                                 disk_work_outstanding = true;
 239                                 break;
 240
 241                         default:
 242                                 compute_io = false;
 243                                 error << string_compose(_("Butler read ahead failure on dstream %1"), (*i)->name()) << endmsg;
 244                                 break;
 245                         }
 246
 247                 }
 248
 249                 if (i != rl->begin() && i != rl->end()) {
 250                         /* we didn't get to all the streams */
 251                         disk_work_outstanding = true;
 252                 }
 253
 254                 if (!err && transport_work_requested()) {
 255                         continue;
 256                 }
 257
 258                 if (compute_io) {
 259                         end = get_microseconds();
 260                         if (end - begin > 0) {
 261                                 _read_data_rate = (float) bytes / (float) (end - begin);
 262                         } else {
 263                                 _read_data_rate = 0; // infinity better
 264                         }
 265                 }
 266
 267                 bytes = 0;
 268                 compute_io = true;
 269                 begin = get_microseconds();
 270
 271                 for (i = rl->begin(); !transport_work_requested() && should_run && i != rl->end(); ++i) {
 272                         // cerr << "write behind for " << (*i)->name () << endl;
 273
 274                         boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 275                         if (!tr) {
 276                                 continue;
 277                         }
 278
 279                         /* note that we still try to flush diskstreams attached to inactive routes
 280                          */
 281
 282                         switch (tr->do_flush (ButlerContext)) {
 283                         case 0:
 284                                 bytes += tr->write_data_count();
 285                                 break;
 286                         case 1:
 287                                 bytes += tr->write_data_count();
 288                                 disk_work_outstanding = true;
 289                                 break;
 290
 291                         default:
 292                                 err++;
 293                                 compute_io = false;
 294                                 error << string_compose(_("Butler write-behind failure on dstream %1"), (*i)->name()) << endmsg;
 295                                 /* don't break - try to flush all streams in case they
 296                                    are split across disks.
 297                                 */
 298                         }
 299                 }
 300
 301                 if (err && _session.actively_recording()) {
 302                         /* stop the transport and try to catch as much possible
 303                            captured state as we can.
 304                         */
 305                         _session.request_stop ();
 306                 }
 307
 308                 if (i != rl->begin() && i != rl->end()) {
 309                         /* we didn't get to all the streams */
 310                         disk_work_outstanding = true;
 311                 }
 312
 313                 if (!err && transport_work_requested()) {
 314                         continue;
 315                 }
 316
 317                 if (compute_io) {
 318                         // there are no apparent users for this calculation?
 319                         end = get_microseconds();
 320                         if (end - begin > 0) {
 321                                 _write_data_rate = (float) bytes / (float) (end - begin);
 322                         } else {
 323                                 _write_data_rate = 0; // Well, infinity would be better
 324                         }
 325                 }
 326
 327                 if (!disk_work_outstanding) {
 328                         _session.refresh_disk_space ();
 329                 }
 330
 331
 332                 {
 333                         Glib::Mutex::Lock lm (request_lock);
 334
 335                         if (should_run && (disk_work_outstanding || transport_work_requested())) {
 336 //                              for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 337 //                                      cerr << "AFTER " << (*i)->name() << ": pb = " << (*i)->playback_buffer_load() << " cp = " << (*i)->capture_buffer_load() << endl;
 338 //                              }
 339
 340                                 continue;
 341                         }
 342
 343                         paused.signal();
 344                 }
 345
 346                 empty_pool_trash ();
 347         }
 348
 349         pthread_exit_pbd (0);
 350         /*NOTREACHED*/
 351         return (0);
 352 }
 353
 354 void
 355 Butler::schedule_transport_work ()
 356 {
 357         g_atomic_int_inc (&should_do_transport_work);
 358         summon ();
 359 }
 360
 361 void
 362 Butler::summon ()
 363 {
 364         char c = Request::Run;
 365         ::write (request_pipe[1], &c, 1);
 366 }
 367
 368 void
 369 Butler::stop ()
 370 {
 371         Glib::Mutex::Lock lm (request_lock);
 372         char c = Request::Pause;
 373         ::write (request_pipe[1], &c, 1);
 374         paused.wait(request_lock);
 375 }
 376
 377 void
 378 Butler::wait_until_finished ()
 379 {
 380         Glib::Mutex::Lock lm (request_lock);
 381         char c = Request::Wake;
 382         ::write (request_pipe[1], &c, 1);
 383         paused.wait(request_lock);
 384 }
 385
 386 bool
 387 Butler::transport_work_requested () const
 388 {
 389         return g_atomic_int_get(&should_do_transport_work);
 390 }
 391
 392 float
 393 Butler::read_data_rate () const
 394 {
 395         /* disk i/o in excess of 10000MB/sec indicate the buffer cache
 396            in action. ignore it.
 397         */
 398         return _read_data_rate > 10485.7600000f ? 0.0f : _read_data_rate;
 399 }
 400
 401 float
 402 Butler::write_data_rate () const
 403 {
 404         /* disk i/o in excess of 10000MB/sec indicate the buffer cache
 405            in action. ignore it.
 406         */
 407         return _write_data_rate > 10485.7600000f ? 0.0f : _write_data_rate;
 408 }
 409
 410 void
 411 Butler::empty_pool_trash ()
 412 {
 413         /* look in the trash, deleting empty pools until we come to one that is not empty */
 414
 415         RingBuffer<CrossThreadPool*>::rw_vector vec;
 416         pool_trash.get_read_vector (&vec);
 417
 418         guint deleted = 0;
 419
 420         for (int i = 0; i < 2; ++i) {
 421                 for (guint j = 0; j < vec.len[i]; ++j) {
 422                         if (vec.buf[i][j]->empty()) {
 423                                 delete vec.buf[i][j];
 424                                 ++deleted;
 425                         } else {
 426                                 /* found a non-empty pool, so stop deleting */
 427                                 if (deleted) {
 428                                         pool_trash.increment_read_idx (deleted);
 429                                 }
 430                                 return;
 431                         }
 432                 }
 433         }
 434
 435         if (deleted) {
 436                 pool_trash.increment_read_idx (deleted);
 437         }
 438 }
 439
 440 void
 441 Butler::drop_references ()
 442 {
 443         SessionEvent::pool->set_trash (0);
 444 }
 445
 446
 447 } // namespace ARDOUR
 448