ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/rt/raypcalls.c
Revision: 2.6
Committed: Tue Mar 30 16:13:01 2004 UTC (20 years, 1 month ago) by schorsch
Content type: text/plain
Branch: MAIN
Changes since 2.5: +45 -29 lines
Log Message:
Continued ANSIfication. There are only bits and pieces left now.

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: raypcalls.c,v 2.5 2003/07/27 22:12:03 schorsch Exp $";
3 #endif
4 /*
5 * raypcalls.c - interface for parallel rendering using Radiance
6 *
7 * External symbols declared in ray.h
8 */
9
10 #include "copyright.h"
11
12 /*
13 * These calls are designed similarly to the ones in raycalls.c,
14 * but allow for multiple rendering processes on the same host
15 * machine. There is no sense in specifying more child processes
16 * than you have processors, but one child may help by allowing
17 * asynchronous ray computation in an interactive program, and
18 * will protect the caller from fatal rendering errors.
19 *
20 * You should first read and undrstand the header in raycalls.c,
21 * as some things are explained there that are not repated here.
22 *
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
28 * memory overhead, since all the static data are shared
29 * between processes. Rays are then traced using a simple
30 * queuing mechanism, explained below.
31 *
32 * The ray queue holds as many rays as there are rendering
33 * processes. Rays are queued and returned by a single
34 * ray_pqueue() call. A ray_pqueue() return
35 * value of 0 indicates that no rays are ready
36 * and the queue is not yet full. A return value of 1
37 * indicates that a ray was returned, though it is probably
38 * not the one you just requested. Rays may be identified by
39 * the rno member of the RAY struct, which is incremented
40 * by the rayorigin() call, or may be set explicitly by
41 * the caller. Below is an example call sequence:
42 *
43 * myRay.rorg = ( ray origin point )
44 * myRay.rdir = ( normalized ray direction )
45 * myRay.rmax = ( maximum length, or zero for no limit )
46 * rayorigin(&myRay, NULL, PRIMARY, 1.0);
47 * myRay.rno = ( my personal ray identifier )
48 * if (ray_pqueue(&myRay) == 1)
49 * { do something with results }
50 *
51 * Note the differences between this and the simpler ray_trace()
52 * call. In particular, the call may or may not return a value
53 * in the passed ray structure. Also, you need to call rayorigin()
54 * yourself, which is normally for you by ray_trace(). The
55 * great thing is that ray_pqueue() will trace rays faster in
56 * proportion to the number of CPUs you have available on your
57 * system. If the ray queue is full before the call, ray_pqueue()
58 * will block until a result is ready so it can queue this one.
59 * The global int ray_pnidle indicates the number of currently idle
60 * children. If you want to check for completed rays without blocking,
61 * or get the results from rays that have been queued without
62 * queuing any new ones, the ray_presult() call is for you:
63 *
64 * if (ray_presult(&myRay, 1) == 1)
65 * { do something with results }
66 *
67 * If the second argument is 1, the call won't block when
68 * results aren't ready, but will immediately return 0.
69 * If the second argument is 0, the call will block
70 * until a value is available, returning 0 only if the
71 * queue is completely empty. A negative return value
72 * indicates that a rendering process died. If this
73 * happens, ray_close(0) is automatically called to close
74 * all child processes, and ray_pnprocs is set to zero.
75 *
76 * If you just want to fill the ray queue without checking for
77 * results, check ray_pnidle and call ray_psend():
78 *
79 * while (ray_pnidle) {
80 * ( set up ray )
81 * ray_psend(&myRay);
82 * }
83 *
84 * The ray_presult() and/or ray_pqueue() functions may then be
85 * called to read back the results.
86 *
87 * When you are done, you may call ray_pdone(1) to close
88 * all child processes and clean up memory used by Radiance.
89 * Any queued ray calculations will be awaited and discarded.
90 * As with ray_done(), ray_pdone(0) hangs onto data files
91 * and fonts that are likely to be used in subsequent renderings.
92 * Whether you want to bother cleaning up memory or not, you
93 * should at least call ray_pclose(0) to clean the child processes.
94 *
95 * Warning: You cannot affect any of the rendering processes
96 * by changing global parameter values onece ray_pinit() has
97 * been called. Changing global parameters will have no effect
98 * until the next call to ray_pinit(), which restarts everything.
99 * If you just want to reap children so that you can alter the
100 * rendering parameters without reloading the scene, use the
101 * ray_pclose(0) and ray_popen(nproc) calls to close
102 * then restart the child processes.
103 *
104 * Note: These routines are written to coordinate with the
105 * definitions in raycalls.c, and in fact depend on them.
106 * If you want to trace a ray and get a result synchronously,
107 * use the ray_trace() call to compute it in the parent process.
108 *
109 * Note: One of the advantages of using separate processes
110 * is that it gives the calling program some immunity from
111 * fatal rendering errors. As discussed in raycalls.c,
112 * Radiance tends to throw up its hands and exit at the
113 * first sign of trouble, calling quit() to return control
114 * to the system. Although you can avoid exit() with
115 * your own longjmp() in quit(), the cleanup afterwards
116 * is always suspect. Through the use of subprocesses,
117 * we avoid this pitfall by closing the processes and
118 * returning a negative value from ray_pqueue() or
119 * ray_presult(). If you get a negative value from either
120 * of these calls, you can assume that the processes have
121 * been cleaned up with a call to ray_close(), though you
122 * will have to call ray_pdone() yourself if you want to
123 * free memory. Obviously, you cannot continue rendering,
124 * but otherwise your process should not be compromised.
125 */
126
127 #include <stdio.h>
128 #include <sys/types.h>
129 #include <sys/wait.h> /* XXX platform */
130
131 #include "rtprocess.h"
132 #include "ray.h"
133 #include "ambient.h"
134 #include "selcall.h"
135
136 #ifndef RAYQLEN
137 #define RAYQLEN 16 /* # rays to send at once */
138 #endif
139
140 #ifndef MAX_RPROCS
141 #if (FD_SETSIZE/2-4 < 64)
142 #define MAX_NPROCS (FD_SETSIZE/2-4)
143 #else
144 #define MAX_NPROCS 64 /* max. # rendering processes */
145 #endif
146 #endif
147
148 extern char *shm_boundary; /* boundary of shared memory */
149
150 int ray_pnprocs = 0; /* number of child processes */
151 int ray_pnidle = 0; /* number of idle children */
152
153 static struct child_proc {
154 int pid; /* child process id */
155 int fd_send; /* write to child here */
156 int fd_recv; /* read from child here */
157 int npending; /* # rays in process */
158 unsigned long rno[RAYQLEN]; /* working on these rays */
159 } r_proc[MAX_NPROCS]; /* our child processes */
160
161 static RAY r_queue[2*RAYQLEN]; /* ray i/o buffer */
162 static int r_send_next; /* next send ray placement */
163 static int r_recv_first; /* position of first unreported ray */
164 static int r_recv_next; /* next receive ray placement */
165
166 #define sendq_full() (r_send_next >= RAYQLEN)
167
168 static int ray_pflush(void);
169 static void ray_pchild(int fd_in, int fd_out);
170
171
172 extern void
173 ray_pinit( /* initialize ray-tracing processes */
174 char *otnm,
175 int nproc
176 )
177 {
178 if (nobjects > 0) /* close old calculation */
179 ray_pdone(0);
180
181 ray_init(otnm); /* load the shared scene */
182
183 preload_objs(); /* preload auxiliary data */
184
185 /* set shared memory boundary */
186 shm_boundary = (char *)malloc(16);
187 strcpy(shm_boundary, "SHM_BOUNDARY");
188
189 r_send_next = 0; /* set up queue */
190 r_recv_first = r_recv_next = RAYQLEN;
191
192 ray_popen(nproc); /* fork children */
193 }
194
195
196 static int
197 ray_pflush(void) /* send queued rays to idle children */
198 {
199 int nc, n, nw, i, sfirst;
200
201 if ((ray_pnidle <= 0) | (r_send_next <= 0))
202 return(0); /* nothing we can send */
203
204 sfirst = 0; /* divvy up labor */
205 nc = ray_pnidle;
206 for (i = ray_pnprocs; nc && i--; ) {
207 if (r_proc[i].npending > 0)
208 continue; /* child looks busy */
209 n = (r_send_next - sfirst)/nc--;
210 if (!n)
211 continue;
212 /* smuggle set size in crtype */
213 r_queue[sfirst].crtype = n;
214 nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
215 sizeof(RAY)*n);
216 if (nw != sizeof(RAY)*n)
217 return(-1); /* write error */
218 r_proc[i].npending = n;
219 while (n--) /* record ray IDs */
220 r_proc[i].rno[n] = r_queue[sfirst+n].rno;
221 sfirst += r_proc[i].npending;
222 ray_pnidle--; /* now she's busy */
223 }
224 if (sfirst != r_send_next)
225 error(CONSISTENCY, "code screwup in ray_pflush");
226 r_send_next = 0;
227 return(sfirst); /* return total # sent */
228 }
229
230
231 extern void
232 ray_psend( /* add a ray to our send queue */
233 RAY *r
234 )
235 {
236 if (r == NULL)
237 return;
238 /* flush output if necessary */
239 if (sendq_full() && ray_pflush() <= 0)
240 error(INTERNAL, "ray_pflush failed in ray_psend");
241
242 r_queue[r_send_next] = *r;
243 r_send_next++;
244 }
245
246
247 extern int
248 ray_pqueue( /* queue a ray for computation */
249 RAY *r
250 )
251 {
252 if (r == NULL)
253 return(0);
254 /* check for full send queue */
255 if (sendq_full()) {
256 RAY mySend;
257 int rval;
258 mySend = *r;
259 /* wait for a result */
260 rval = ray_presult(r, 0);
261 /* put new ray in queue */
262 r_queue[r_send_next] = mySend;
263 r_send_next++;
264 return(rval); /* done */
265 }
266 /* add ray to send queue */
267 r_queue[r_send_next] = *r;
268 r_send_next++;
269 /* check for returned ray... */
270 if (r_recv_first >= r_recv_next)
271 return(0);
272 /* ...one is sitting in queue */
273 *r = r_queue[r_recv_first];
274 r_recv_first++;
275 return(1);
276 }
277
278
279 extern int
280 ray_presult( /* check for a completed ray */
281 RAY *r,
282 int poll
283 )
284 {
285 static struct timeval tpoll; /* zero timeval struct */
286 static fd_set readset, errset;
287 int n, ok;
288 register int pn;
289
290 if (r == NULL)
291 return(0);
292 /* check queued results first */
293 if (r_recv_first < r_recv_next) {
294 *r = r_queue[r_recv_first];
295 r_recv_first++;
296 return(1);
297 }
298 n = ray_pnprocs - ray_pnidle; /* pending before flush? */
299
300 if (ray_pflush() < 0) /* send new rays to process */
301 return(-1);
302 /* reset receive queue */
303 r_recv_first = r_recv_next = RAYQLEN;
304
305 if (!poll) /* count newly sent unless polling */
306 n = ray_pnprocs - ray_pnidle;
307 if (n <= 0) /* return if nothing to await */
308 return(0);
309 getready: /* any children waiting for us? */
310 for (pn = ray_pnprocs; pn--; )
311 if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
312 FD_ISSET(r_proc[pn].fd_recv, &errset))
313 break;
314 /* call select if we must */
315 if (pn < 0) {
316 FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
317 for (pn = ray_pnprocs; pn--; ) {
318 if (r_proc[pn].npending > 0)
319 FD_SET(r_proc[pn].fd_recv, &readset);
320 FD_SET(r_proc[pn].fd_recv, &errset);
321 if (r_proc[pn].fd_recv >= n)
322 n = r_proc[pn].fd_recv + 1;
323 }
324 /* find out who is ready */
325 while ((n = select(n, &readset, (fd_set *)NULL, &errset,
326 poll ? &tpoll : (struct timeval *)NULL)) < 0)
327 if (errno != EINTR) {
328 error(WARNING,
329 "select call failed in ray_presult");
330 ray_pclose(0);
331 return(-1);
332 }
333 if (n > 0) /* go back and get it */
334 goto getready;
335 return(0); /* else poll came up empty */
336 }
337 if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
338 error(CONSISTENCY, "buffer shortage in ray_presult()");
339
340 /* read rendered ray data */
341 n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
342 sizeof(RAY)*r_proc[pn].npending);
343 if (n > 0) {
344 r_recv_next += n/sizeof(RAY);
345 ok = (n == sizeof(RAY)*r_proc[pn].npending);
346 } else
347 ok = 0;
348 /* reset child's status */
349 FD_CLR(r_proc[pn].fd_recv, &readset);
350 if (n <= 0)
351 FD_CLR(r_proc[pn].fd_recv, &errset);
352 r_proc[pn].npending = 0;
353 ray_pnidle++;
354 /* check for rendering errors */
355 if (!ok) {
356 ray_pclose(0); /* process died -- clean up */
357 return(-1);
358 }
359 /* preen returned rays */
360 for (n = r_recv_next - r_recv_first; n--; ) {
361 register RAY *rp = &r_queue[r_recv_first + n];
362 rp->rno = r_proc[pn].rno[n];
363 rp->parent = NULL;
364 rp->newcset = rp->clipset = NULL;
365 rp->rox = NULL;
366 rp->slights = NULL;
367 }
368 /* return first ray received */
369 *r = r_queue[r_recv_first];
370 r_recv_first++;
371 return(1);
372 }
373
374
375 extern void
376 ray_pdone( /* reap children and free data */
377 int freall
378 )
379 {
380 ray_pclose(0); /* close child processes */
381
382 if (shm_boundary != NULL) { /* clear shared memory boundary */
383 free((void *)shm_boundary);
384 shm_boundary = NULL;
385 }
386 ray_done(freall); /* free rendering data */
387 }
388
389
390 static void
391 ray_pchild( /* process rays (never returns) */
392 int fd_in,
393 int fd_out
394 )
395 {
396 int n;
397 register int i;
398 /* read each ray request set */
399 while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
400 int n2;
401 if (n % sizeof(RAY))
402 break;
403 n /= sizeof(RAY);
404 /* get smuggled set length */
405 n2 = r_queue[0].crtype - n;
406 if (n2 < 0)
407 error(INTERNAL, "buffer over-read in ray_pchild");
408 if (n2 > 0) { /* read the rest of the set */
409 i = readbuf(fd_in, (char *)(r_queue+n),
410 sizeof(RAY)*n2);
411 if (i != sizeof(RAY)*n2)
412 break;
413 n += n2;
414 }
415 /* evaluate rays */
416 for (i = 0; i < n; i++) {
417 r_queue[i].crtype = r_queue[i].rtype;
418 r_queue[i].parent = NULL;
419 r_queue[i].clipset = NULL;
420 r_queue[i].slights = NULL;
421 r_queue[i].revf = raytrace;
422 samplendx++;
423 rayclear(&r_queue[i]);
424 rayvalue(&r_queue[i]);
425 }
426 /* write back our results */
427 i = writebuf(fd_out, (char *)r_queue, sizeof(RAY)*n);
428 if (i != sizeof(RAY)*n)
429 error(SYSTEM, "write error in ray_pchild");
430 }
431 if (n)
432 error(SYSTEM, "read error in ray_pchild");
433 ambsync();
434 quit(0); /* normal exit */
435 }
436
437
438 extern void
439 ray_popen( /* open the specified # processes */
440 int nadd
441 )
442 {
443 /* check if our table has room */
444 if (ray_pnprocs + nadd > MAX_NPROCS)
445 nadd = MAX_NPROCS - ray_pnprocs;
446 if (nadd <= 0)
447 return;
448 fflush(stderr); /* clear pending output */
449 fflush(stdout);
450 while (nadd--) { /* fork each new process */
451 int p0[2], p1[2];
452 if (pipe(p0) < 0 || pipe(p1) < 0)
453 error(SYSTEM, "cannot create pipe");
454 if ((r_proc[ray_pnprocs].pid = fork()) == 0) {
455 int pn; /* close others' descriptors */
456 for (pn = ray_pnprocs; pn--; ) {
457 close(r_proc[pn].fd_send);
458 close(r_proc[pn].fd_recv);
459 }
460 close(p0[0]); close(p1[1]);
461 /* following call never returns */
462 ray_pchild(p1[0], p0[1]);
463 }
464 if (r_proc[ray_pnprocs].pid < 0)
465 error(SYSTEM, "cannot fork child process");
466 close(p1[0]); close(p0[1]);
467 r_proc[ray_pnprocs].fd_send = p1[1];
468 r_proc[ray_pnprocs].fd_recv = p0[0];
469 r_proc[ray_pnprocs].npending = 0;
470 ray_pnprocs++;
471 ray_pnidle++;
472 }
473 }
474
475
476 extern void
477 ray_pclose( /* close one or more child processes */
478 int nsub
479 )
480 {
481 static int inclose = 0;
482 RAY res;
483 /* check recursion */
484 if (inclose)
485 return;
486 inclose++;
487 /* check argument */
488 if ((nsub <= 0) | (nsub > ray_pnprocs))
489 nsub = ray_pnprocs;
490 /* clear our ray queue */
491 while (ray_presult(&res,0) > 0)
492 ;
493 /* clean up children */
494 while (nsub--) {
495 int status;
496 ray_pnprocs--;
497 close(r_proc[ray_pnprocs].fd_recv);
498 close(r_proc[ray_pnprocs].fd_send);
499 while (wait(&status) != r_proc[ray_pnprocs].pid)
500 ;
501 if (status) {
502 sprintf(errmsg,
503 "rendering process %d exited with code %d",
504 r_proc[ray_pnprocs].pid, status>>8);
505 error(WARNING, errmsg);
506 }
507 ray_pnidle--;
508 }
509 inclose--;
510 }
511
512
513 void
514 quit(ec) /* make sure exit is called */
515 int ec;
516 {
517 exit(ec);
518 }