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root/radiance/ray/src/rt/raypcalls.c
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Comparing ray/src/rt/raypcalls.c (file contents):
Revision 2.6 by schorsch, Tue Mar 30 16:13:01 2004 UTC vs.
Revision 2.16 by greg, Sat Sep 15 02:47:56 2007 UTC

# Line 23 | Line 23 | static const char      RCSid[] = "$Id$";
23   *  The first step is opening one or more rendering processes
24   *  with a call to ray_pinit(oct, nproc).  Before calling fork(),
25   *  ray_pinit() loads the octree and data structures into the
26 < *  caller's memory.  This permits all sorts of queries that
27 < *  wouldn't be possible otherwise, without causing any real
26 > *  caller's memory, and ray_popen() synchronizes the ambient
27 > *  file, if any.  Shared memory permits all sorts of queries
28 > *  that wouldn't be possible otherwise, without causing any real
29   *  memory overhead, since all the static data are shared
30   *  between processes.  Rays are then traced using a simple
31   *  queuing mechanism, explained below.
32   *
33 < *  The ray queue holds as many rays as there are rendering
34 < *  processes.  Rays are queued and returned by a single
33 > *  The ray queue buffers RAYQLEN rays before sending to
34 > *  children, each of which may internally buffer RAYQLEN rays.
35 > *
36 > *  Rays are queued and returned by a single
37   *  ray_pqueue() call.  A ray_pqueue() return
38   *  value of 0 indicates that no rays are ready
39   *  and the queue is not yet full.  A return value of 1
# Line 43 | Line 46 | static const char      RCSid[] = "$Id$";
46   *      myRay.rorg = ( ray origin point )
47   *      myRay.rdir = ( normalized ray direction )
48   *      myRay.rmax = ( maximum length, or zero for no limit )
49 < *      rayorigin(&myRay, NULL, PRIMARY, 1.0);
49 > *      rayorigin(&myRay, PRIMARY, NULL, NULL);
50   *      myRay.rno = ( my personal ray identifier )
51   *      if (ray_pqueue(&myRay) == 1)
52   *              { do something with results }
# Line 51 | Line 54 | static const char      RCSid[] = "$Id$";
54   *  Note the differences between this and the simpler ray_trace()
55   *  call.  In particular, the call may or may not return a value
56   *  in the passed ray structure.  Also, you need to call rayorigin()
57 < *  yourself, which is normally for you by ray_trace().  The
58 < *  great thing is that ray_pqueue() will trace rays faster in
57 > *  yourself, which is normally called for you by ray_trace().  The
58 > *  benefit is that ray_pqueue() will trace rays faster in
59   *  proportion to the number of CPUs you have available on your
60   *  system.  If the ray queue is full before the call, ray_pqueue()
61   *  will block until a result is ready so it can queue this one.
# Line 81 | Line 84 | static const char      RCSid[] = "$Id$";
84   *              ray_psend(&myRay);
85   *      }
86   *
87 < *  The ray_presult() and/or ray_pqueue() functions may then be
88 < *  called to read back the results.
87 > *  Note that it is a fatal error to call ra_psend() when
88 > *  ray_pnidle is zero.  The ray_presult() and/or ray_pqueue()
89 > *  functions may be called subsequently to read back the results.
90   *
91   *  When you are done, you may call ray_pdone(1) to close
92   *  all child processes and clean up memory used by Radiance.
# Line 99 | Line 103 | static const char      RCSid[] = "$Id$";
103   *  If you just want to reap children so that you can alter the
104   *  rendering parameters without reloading the scene, use the
105   *  ray_pclose(0) and ray_popen(nproc) calls to close
106 < *  then restart the child processes.
106 > *  then restart the child processes after the changes are made.
107   *
108   *  Note:  These routines are written to coordinate with the
109   *  definitions in raycalls.c, and in fact depend on them.
110   *  If you want to trace a ray and get a result synchronously,
111   *  use the ray_trace() call to compute it in the parent process.
112 + *  This will not interfere with any subprocess calculations,
113 + *  but beware that a fatal error may end with a call to quit().
114   *
115   *  Note:  One of the advantages of using separate processes
116   *  is that it gives the calling program some immunity from
117   *  fatal rendering errors.  As discussed in raycalls.c,
118   *  Radiance tends to throw up its hands and exit at the
119   *  first sign of trouble, calling quit() to return control
120 < *  to the system.  Although you can avoid exit() with
120 > *  to the top level.  Although you can avoid exit() with
121   *  your own longjmp() in quit(), the cleanup afterwards
122   *  is always suspect.  Through the use of subprocesses,
123   *  we avoid this pitfall by closing the processes and
# Line 120 | Line 126 | static const char      RCSid[] = "$Id$";
126   *  of these calls, you can assume that the processes have
127   *  been cleaned up with a call to ray_close(), though you
128   *  will have to call ray_pdone() yourself if you want to
129 < *  free memory.  Obviously, you cannot continue rendering,
130 < *  but otherwise your process should not be compromised.
129 > *  free memory.  Obviously, you cannot continue rendering
130 > *  without risking further errors, but otherwise your
131 > *  process should not be compromised.
132   */
133  
134   #include <stdio.h>
# Line 134 | Line 141 | static const char      RCSid[] = "$Id$";
141   #include  "selcall.h"
142  
143   #ifndef RAYQLEN
144 < #define RAYQLEN         16              /* # rays to send at once */
144 > #define RAYQLEN         12              /* # rays to send at once */
145   #endif
146  
147   #ifndef MAX_RPROCS
# Line 166 | Line 173 | static int     r_recv_next;            /* next receive ray placement
173   #define sendq_full()    (r_send_next >= RAYQLEN)
174  
175   static int ray_pflush(void);
176 < static void ray_pchild(int      fd_in, int      fd_out);
176 > static void ray_pchild(int fd_in, int fd_out);
177  
178  
179   extern void
# Line 239 | Line 246 | ray_psend(                     /* add a ray to our send queue */
246          if (sendq_full() && ray_pflush() <= 0)
247                  error(INTERNAL, "ray_pflush failed in ray_psend");
248  
249 <        r_queue[r_send_next] = *r;
243 <        r_send_next++;
249 >        r_queue[r_send_next++] = *r;
250   }
251  
252  
# Line 259 | Line 265 | ray_pqueue(                    /* queue a ray for computation */
265                                          /* wait for a result */
266                  rval = ray_presult(r, 0);
267                                          /* put new ray in queue */
268 <                r_queue[r_send_next] = mySend;
263 <                r_send_next++;
268 >                r_queue[r_send_next++] = mySend;
269                  return(rval);           /* done */
270          }
271 <                                        /* add ray to send queue */
272 <        r_queue[r_send_next] = *r;
268 <        r_send_next++;
271 >                                        /* else add ray to send queue */
272 >        r_queue[r_send_next++] = *r;
273                                          /* check for returned ray... */
274          if (r_recv_first >= r_recv_next)
275                  return(0);
276                                          /* ...one is sitting in queue */
277 <        *r = r_queue[r_recv_first];
274 <        r_recv_first++;
277 >        *r = r_queue[r_recv_first++];
278          return(1);
279   }
280  
# Line 291 | Line 294 | ray_presult(           /* check for a completed ray */
294                  return(0);
295                                          /* check queued results first */
296          if (r_recv_first < r_recv_next) {
297 <                *r = r_queue[r_recv_first];
295 <                r_recv_first++;
297 >                *r = r_queue[r_recv_first++];
298                  return(1);
299          }
300          n = ray_pnprocs - ray_pnidle;   /* pending before flush? */
# Line 306 | Line 308 | ray_presult(           /* check for a completed ray */
308                  n = ray_pnprocs - ray_pnidle;
309          if (n <= 0)                     /* return if nothing to await */
310                  return(0);
311 +        if (!poll && ray_pnprocs == 1)  /* one process -> skip select() */
312 +                FD_SET(r_proc[0].fd_recv, &readset);
313 +
314   getready:                               /* any children waiting for us? */
315          for (pn = ray_pnprocs; pn--; )
316                  if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
# Line 366 | Line 371 | getready:                              /* any children waiting for us? */
371                  rp->slights = NULL;
372          }
373                                          /* return first ray received */
374 <        *r = r_queue[r_recv_first];
370 <        r_recv_first++;
374 >        *r = r_queue[r_recv_first++];
375          return(1);
376   }
377  
# Line 395 | Line 399 | ray_pchild(    /* process rays (never returns) */
399   {
400          int     n;
401          register int    i;
402 +                                        /* flag child process for quit() */
403 +        ray_pnprocs = -1;
404                                          /* read each ray request set */
405          while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
406                  int     n2;
407 <                if (n % sizeof(RAY))
407 >                if (n < sizeof(RAY))
408                          break;
403 –                n /= sizeof(RAY);
409                                          /* get smuggled set length */
410 <                n2 = r_queue[0].crtype - n;
410 >                n2 = sizeof(RAY)*r_queue[0].crtype - n;
411                  if (n2 < 0)
412                          error(INTERNAL, "buffer over-read in ray_pchild");
413                  if (n2 > 0) {           /* read the rest of the set */
414 <                        i = readbuf(fd_in, (char *)(r_queue+n),
415 <                                        sizeof(RAY)*n2);
411 <                        if (i != sizeof(RAY)*n2)
414 >                        i = readbuf(fd_in, (char *)r_queue + n, n2);
415 >                        if (i != n2)
416                                  break;
417                          n += n2;
418                  }
419 +                n /= sizeof(RAY);
420                                          /* evaluate rays */
421                  for (i = 0; i < n; i++) {
422                          r_queue[i].crtype = r_queue[i].rtype;
423                          r_queue[i].parent = NULL;
424                          r_queue[i].clipset = NULL;
425                          r_queue[i].slights = NULL;
421 –                        r_queue[i].revf = raytrace;
426                          samplendx++;
427                          rayclear(&r_queue[i]);
428                          rayvalue(&r_queue[i]);
# Line 445 | Line 449 | ray_popen(                     /* open the specified # processes */
449                  nadd = MAX_NPROCS - ray_pnprocs;
450          if (nadd <= 0)
451                  return;
452 <        fflush(stderr);                 /* clear pending output */
453 <        fflush(stdout);
452 >        ambsync();                      /* load any new ambient values */
453 >        fflush(NULL);                   /* clear pending output */
454          while (nadd--) {                /* fork each new process */
455                  int     p0[2], p1[2];
456                  if (pipe(p0) < 0 || pipe(p1) < 0)
# Line 464 | Line 468 | ray_popen(                     /* open the specified # processes */
468                  if (r_proc[ray_pnprocs].pid < 0)
469                          error(SYSTEM, "cannot fork child process");
470                  close(p1[0]); close(p0[1]);
471 +                /*
472 +                 * Close write stream on exec to avoid multiprocessing deadlock.
473 +                 * No use in read stream without it, so set flag there as well.
474 +                 */
475 +                fcntl(p1[1], F_SETFD, FD_CLOEXEC);
476 +                fcntl(p0[0], F_SETFD, FD_CLOEXEC);
477                  r_proc[ray_pnprocs].fd_send = p1[1];
478                  r_proc[ray_pnprocs].fd_recv = p0[0];
479                  r_proc[ray_pnprocs].npending = 0;
# Line 496 | Line 506 | ray_pclose(            /* close one or more child processes */
506                  ray_pnprocs--;
507                  close(r_proc[ray_pnprocs].fd_recv);
508                  close(r_proc[ray_pnprocs].fd_send);
509 <                while (wait(&status) != r_proc[ray_pnprocs].pid)
510 <                        ;
509 >                if (waitpid(r_proc[ray_pnprocs].pid, &status, 0) < 0)
510 >                        status = 127<<8;
511                  if (status) {
512                          sprintf(errmsg,
513                                  "rendering process %d exited with code %d",
# Line 514 | Line 524 | void
524   quit(ec)                        /* make sure exit is called */
525   int     ec;
526   {
527 +        if (ray_pnprocs > 0)    /* close children if any */
528 +                ray_pclose(0);          
529          exit(ec);
530   }

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