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