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 {
  47         g_atomic_int_set(&should_do_transport_work, 0);
  48 }
  49
  50 Butler::~Butler()
  51 {
  52         terminate_thread ();
  53 }
  54
  55 int
  56 Butler::start_thread()
  57 {
  58         const float rate = (float)_session.frame_rate();
  59
  60         /* size is in Samples, not bytes */
  61         audio_dstream_buffer_size = (uint32_t) floor (Config->get_audio_track_buffer_seconds() * rate);
  62
  63         /* size is in bytes
  64          * XXX: Jack needs to tell us the MIDI buffer size
  65          * (i.e. how many MIDI bytes we might see in a cycle)
  66          */
  67         midi_dstream_buffer_size = (uint32_t) floor (Config->get_midi_track_buffer_seconds() * rate);
  68
  69         MidiDiskstream::set_readahead_frames ((nframes_t)(Config->get_midi_readahead() * rate));
  70
  71         Crossfade::set_buffer_size (audio_dstream_buffer_size);
  72
  73         should_run = false;
  74
  75         if (pipe (request_pipe)) {
  76                 error << string_compose(_("Cannot create transport request signal pipe (%1)"),
  77                                 strerror (errno)) << endmsg;
  78                 return -1;
  79         }
  80
  81         if (fcntl (request_pipe[0], F_SETFL, O_NONBLOCK)) {
  82                 error << string_compose(_("UI: cannot set O_NONBLOCK on butler request pipe (%1)"),
  83                                 strerror (errno)) << endmsg;
  84                 return -1;
  85         }
  86
  87         if (fcntl (request_pipe[1], F_SETFL, O_NONBLOCK)) {
  88                 error << string_compose(_("UI: cannot set O_NONBLOCK on butler request pipe (%1)"),
  89                                 strerror (errno)) << endmsg;
  90                 return -1;
  91         }
  92
  93         if (pthread_create_and_store ("disk butler", &thread, _thread_work, this)) {
  94                 error << _("Session: could not create butler thread") << endmsg;
  95                 return -1;
  96         }
  97
  98         //pthread_detach (thread);
  99
 100         return 0;
 101 }
 102
 103 void
 104 Butler::terminate_thread ()
 105 {
 106         if (thread) {
 107                 void* status;
 108                 const char c = Request::Quit;
 109                 ::write (request_pipe[1], &c, 1);
 110                 pthread_join (thread, &status);
 111         }
 112 }
 113
 114 void *
 115 Butler::_thread_work (void* arg)
 116 {
 117         SessionEvent::create_per_thread_pool ("butler events", 64);
 118         pthread_set_name (X_("butler"));
 119         return ((Butler *) arg)->thread_work ();
 120 }
 121
 122 void *
 123 Butler::thread_work ()
 124 {
 125         uint32_t err = 0;
 126         int32_t bytes;
 127         bool compute_io;
 128         microseconds_t begin, end;
 129
 130         struct pollfd pfd[1];
 131         bool disk_work_outstanding = false;
 132         Session::DiskstreamList::iterator i;
 133
 134         while (true) {
 135                 pfd[0].fd = request_pipe[0];
 136                 pfd[0].events = POLLIN|POLLERR|POLLHUP;
 137
 138                 if (poll (pfd, 1, (disk_work_outstanding ? 0 : -1)) < 0) {
 139
 140                         if (errno == EINTR) {
 141                                 continue;
 142                         }
 143
 144                         error << string_compose (_("poll on butler request pipe failed (%1)"),
 145                                           strerror (errno))
 146                               << endmsg;
 147                         break;
 148                 }
 149
 150                 if (pfd[0].revents & ~POLLIN) {
 151                         error << string_compose (_("Error on butler thread request pipe: fd=%1 err=%2"), pfd[0].fd, pfd[0].revents) << endmsg;
 152                         break;
 153                 }
 154
 155                 if (pfd[0].revents & POLLIN) {
 156
 157                         char req;
 158
 159                         /* empty the pipe of all current requests */
 160
 161                         while (1) {
 162                                 size_t nread = ::read (request_pipe[0], &req, sizeof (req));
 163                                 if (nread == 1) {
 164
 165                                         switch ((Request::Type) req) {
 166
 167                                         case Request::Wake:
 168                                                 break;
 169
 170                                         case Request::Run:
 171                                                 should_run = true;
 172                                                 break;
 173
 174                                         case Request::Pause:
 175                                                 should_run = false;
 176                                                 break;
 177
 178                                         case Request::Quit:
 179                                                 pthread_exit_pbd (0);
 180                                                 /*NOTREACHED*/
 181                                                 break;
 182
 183                                         default:
 184                                                 break;
 185                                         }
 186
 187                                 } else if (nread == 0) {
 188                                         break;
 189                                 } else if (errno == EAGAIN) {
 190                                         break;
 191                                 } else {
 192                                         fatal << _("Error reading from butler request pipe") << endmsg;
 193                                         /*NOTREACHED*/
 194                                 }
 195                         }
 196                 }
 197
 198                 if (transport_work_requested()) {
 199                         _session.butler_transport_work ();
 200                 }
 201
 202                 disk_work_outstanding = false;
 203                 bytes = 0;
 204                 compute_io = true;
 205
 206                 begin = get_microseconds();
 207
 208                 boost::shared_ptr<Session::DiskstreamList> dsl = _session.diskstream_list().reader ();
 209
 210 //              for (i = dsl->begin(); i != dsl->end(); ++i) {
 211 //                      cerr << "BEFORE " << (*i)->name() << ": pb = " << (*i)->playback_buffer_load() << " cp = " << (*i)->capture_buffer_load() << endl;
 212 //              }
 213
 214                 for (i = dsl->begin(); !transport_work_requested() && should_run && i != dsl->end(); ++i) {
 215
 216                         boost::shared_ptr<Diskstream> ds = *i;
 217
 218                         /* don't read inactive tracks */
 219
 220                         boost::shared_ptr<IO> io = ds->io();
 221
 222                         if (io && !io->active()) {
 223                                 continue;
 224                         }
 225
 226                         switch (ds->do_refill ()) {
 227                         case 0:
 228                                 bytes += ds->read_data_count();
 229                                 break;
 230                         case 1:
 231                                 bytes += ds->read_data_count();
 232                                 disk_work_outstanding = true;
 233                                 break;
 234
 235                         default:
 236                                 compute_io = false;
 237                                 error << string_compose(_("Butler read ahead failure on dstream %1"), (*i)->name()) << endmsg;
 238                                 break;
 239                         }
 240
 241                 }
 242
 243                 if (i != dsl->end()) {
 244                         /* we didn't get to all the streams */
 245                         disk_work_outstanding = true;
 246                 }
 247
 248                 if (!err && transport_work_requested()) {
 249                         continue;
 250                 }
 251
 252                 if (compute_io) {
 253                         end = get_microseconds();
 254                         if (end - begin > 0) {
 255                                 _read_data_rate = (float) bytes / (float) (end - begin);
 256                         } else {
 257                                 _read_data_rate = 0; // infinity better
 258                         }
 259                 }
 260
 261                 bytes = 0;
 262                 compute_io = true;
 263                 begin = get_microseconds();
 264
 265                 for (i = dsl->begin(); !transport_work_requested() && should_run && i != dsl->end(); ++i) {
 266                         // cerr << "write behind for " << (*i)->name () << endl;
 267
 268                         /* note that we still try to flush diskstreams attached to inactive routes
 269                          */
 270
 271                         switch ((*i)->do_flush (ButlerContext)) {
 272                         case 0:
 273                                 bytes += (*i)->write_data_count();
 274                                 break;
 275                         case 1:
 276                                 bytes += (*i)->write_data_count();
 277                                 disk_work_outstanding = true;
 278                                 break;
 279
 280                         default:
 281                                 err++;
 282                                 compute_io = false;
 283                                 error << string_compose(_("Butler write-behind failure on dstream %1"), (*i)->name()) << endmsg;
 284                                 /* don't break - try to flush all streams in case they
 285                                    are split across disks.
 286                                 */
 287                         }
 288                 }
 289
 290                 if (err && _session.actively_recording()) {
 291                         /* stop the transport and try to catch as much possible
 292                            captured state as we can.
 293                         */
 294                         _session.request_stop ();
 295                 }
 296
 297                 if (i != dsl->end()) {
 298                         /* we didn't get to all the streams */
 299                         disk_work_outstanding = true;
 300                 }
 301
 302                 if (!err && transport_work_requested()) {
 303                         continue;
 304                 }
 305
 306                 if (compute_io) {
 307                         // there are no apparent users for this calculation?
 308                         end = get_microseconds();
 309                         if (end - begin > 0) {
 310                                 _write_data_rate = (float) bytes / (float) (end - begin);
 311                         } else {
 312                                 _write_data_rate = 0; // Well, infinity would be better
 313                         }
 314                 }
 315
 316                 if (!disk_work_outstanding) {
 317                         _session.refresh_disk_space ();
 318                 }
 319
 320
 321                 {
 322                         Glib::Mutex::Lock lm (request_lock);
 323
 324                         if (should_run && (disk_work_outstanding || transport_work_requested())) {
 325 //                              for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 326 //                                      cerr << "AFTER " << (*i)->name() << ": pb = " << (*i)->playback_buffer_load() << " cp = " << (*i)->capture_buffer_load() << endl;
 327 //                              }
 328
 329                                 continue;
 330                         }
 331
 332                         paused.signal();
 333                 }
 334         }
 335
 336         pthread_exit_pbd (0);
 337         /*NOTREACHED*/
 338         return (0);
 339 }
 340
 341 void
 342 Butler::schedule_transport_work ()
 343 {
 344         g_atomic_int_inc (&should_do_transport_work);
 345         summon ();
 346 }
 347
 348 void
 349 Butler::summon ()
 350 {
 351         char c = Request::Run;
 352         ::write (request_pipe[1], &c, 1);
 353 }
 354
 355 void
 356 Butler::stop ()
 357 {
 358         Glib::Mutex::Lock lm (request_lock);
 359         char c = Request::Pause;
 360         ::write (request_pipe[1], &c, 1);
 361         paused.wait(request_lock);
 362 }
 363
 364 void
 365 Butler::wait_until_finished ()
 366 {
 367         Glib::Mutex::Lock lm (request_lock);
 368         char c = Request::Wake;
 369         ::write (request_pipe[1], &c, 1);
 370         paused.wait(request_lock);
 371 }
 372
 373 bool
 374 Butler::transport_work_requested () const
 375 {
 376         return g_atomic_int_get(&should_do_transport_work);
 377 }
 378
 379 float
 380 Butler::read_data_rate () const
 381 {
 382         /* disk i/o in excess of 10000MB/sec indicate the buffer cache
 383            in action. ignore it.
 384         */
 385         return _read_data_rate > 10485.7600000f ? 0.0f : _read_data_rate;
 386 }
 387
 388 float
 389 Butler::write_data_rate () const
 390 {
 391         /* disk i/o in excess of 10000MB/sec indicate the buffer cache
 392            in action. ignore it.
 393         */
 394         return _write_data_rate > 10485.7600000f ? 0.0f : _write_data_rate;
 395 }
 396
 397 } // namespace ARDOUR