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