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root/radiance/ray/src/rt/raypcalls.c
Revision: 2.24
Committed: Sat Dec 12 23:08:13 2009 UTC (14 years, 4 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.23: +9 -8 lines
Log Message:
Bug fixes and performance improvements to rtrace -n option

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: raypcalls.c,v 2.23 2009/12/12 19:01:00 greg 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 processor cores, 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 understand 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, 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 traced using a simple
31 * queuing mechanism, explained below.
32 *
33 * The ray queue buffers RAYQLEN rays before sending to
34 * children, each of which may internally buffer RAYQLEN rays
35 * during evaluation. Rays are not returned in the order
36 * they are sent when multiple processes are open.
37 *
38 * Rays are queued and returned by a single
39 * ray_pqueue() call. A ray_pqueue() return
40 * value of 0 indicates that no rays are ready
41 * and the queue is not yet full. A return value of 1
42 * indicates that a ray was returned, though it is probably
43 * not the one you just requested. Rays may be identified by
44 * the rno member of the RAY struct, which is incremented
45 * by the rayorigin() call, or may be set explicitly by
46 * the caller. Below is an example call sequence:
47 *
48 * myRay.rorg = ( ray origin point )
49 * myRay.rdir = ( normalized ray direction )
50 * myRay.rmax = ( maximum length, or zero for no limit )
51 * rayorigin(&myRay, PRIMARY, NULL, NULL);
52 * myRay.rno = ( my personal ray identifier )
53 * if (ray_pqueue(&myRay) == 1)
54 * { do something with results }
55 *
56 * Note the differences between this and the simpler ray_trace()
57 * call. In particular, the call may or may not return a value
58 * in the passed ray structure. Also, you need to call rayorigin()
59 * yourself, which is normally called for you by ray_trace(). The
60 * benefit is that ray_pqueue() will trace rays faster in
61 * proportion to the number of CPUs you have available on your
62 * system. If the ray queue is full before the call, ray_pqueue()
63 * will block until a result is ready so it can queue this one.
64 * The global int ray_pnidle indicates the number of currently idle
65 * children. If you want to check for completed rays without blocking,
66 * or get the results from rays that have been queued without
67 * queuing any new ones, the ray_presult() call is for you:
68 *
69 * if (ray_presult(&myRay, 1) == 1)
70 * { do something with results }
71 *
72 * If the second argument is 1, the call won't block when
73 * results aren't ready, but will immediately return 0.
74 * (A special value of -1 returns 0 unless a ray is
75 * ready in the queue and no system calls are needed.)
76 * If the second argument is 0, the call will block
77 * until a value is available, returning 0 only if the
78 * queue is completely empty. A negative return value
79 * indicates that a rendering process died. If this
80 * happens, ray_pclose(0) is automatically called to close
81 * all child processes, and ray_pnprocs is set to zero.
82 *
83 * If you just want to fill the ray queue without checking for
84 * results, check ray_pnidle and call ray_psend():
85 *
86 * while (ray_pnidle) {
87 * ( set up ray )
88 * ray_psend(&myRay);
89 * }
90 *
91 * Note that it is a fatal error to call ra_psend() when
92 * ray_pnidle is zero. The ray_presult() and/or ray_pqueue()
93 * functions may be called subsequently to read back the results.
94 *
95 * When you are done, you may call ray_pdone(1) to close
96 * all child processes and clean up memory used by Radiance.
97 * Any queued ray calculations will be awaited and discarded.
98 * As with ray_done(), ray_pdone(0) hangs onto data files
99 * and fonts that are likely to be used in subsequent renderings.
100 * Whether you need to clean up memory or not, you should
101 * at least call ray_pclose(0) to await the child processes.
102 * The caller should define a quit() function that calls
103 * ray_pclose(0) if ray_pnprocs > 0.
104 *
105 * Warning: You cannot affect any of the rendering processes
106 * by changing global parameter values onece ray_pinit() has
107 * been called. Changing global parameters will have no effect
108 * until the next call to ray_pinit(), which restarts everything.
109 * If you just want to reap children so that you can alter the
110 * rendering parameters without reloading the scene, use the
111 * ray_pclose(0) and ray_popen(nproc) calls to close
112 * then restart the child processes after the changes are made.
113 *
114 * Note: These routines are written to coordinate with the
115 * definitions in raycalls.c, and in fact depend on them.
116 * If you want to trace a ray and get a result synchronously,
117 * use the ray_trace() call to compute it in the parent process.
118 * This will not interfere with any subprocess calculations,
119 * but beware that a fatal error may end with a call to quit().
120 *
121 * Note: One of the advantages of using separate processes
122 * is that it gives the calling program some immunity from
123 * fatal rendering errors. As discussed in raycalls.c,
124 * Radiance tends to throw up its hands and exit at the
125 * first sign of trouble, calling quit() to return control
126 * to the top level. Although you can avoid exit() with
127 * your own longjmp() in quit(), the cleanup afterwards
128 * is always suspect. Through the use of subprocesses,
129 * we avoid this pitfall by closing the processes and
130 * returning a negative value from ray_pqueue() or
131 * ray_presult(). If you get a negative value from either
132 * of these calls, you can assume that the processes have
133 * been cleaned up with a call to ray_pclose(), though you
134 * will have to call ray_pdone() yourself if you want to
135 * free memory. Obviously, you cannot continue rendering
136 * without risking further errors, but otherwise your
137 * process should not be compromised.
138 */
139
140 #include "rtprocess.h"
141 #include "ray.h"
142 #include "ambient.h"
143 #include <sys/types.h>
144 #include <sys/wait.h>
145 #include "selcall.h"
146
147 #ifndef RAYQLEN
148 #define RAYQLEN 12 /* # rays to send at once */
149 #endif
150
151 #ifndef MAX_RPROCS
152 #if (FD_SETSIZE/2-4 < 64)
153 #define MAX_NPROCS (FD_SETSIZE/2-4)
154 #else
155 #define MAX_NPROCS 64 /* max. # rendering processes */
156 #endif
157 #endif
158
159 extern char *shm_boundary; /* boundary of shared memory */
160
161 int ray_pnprocs = 0; /* number of child processes */
162 int ray_pnidle = 0; /* number of idle children */
163
164 static struct child_proc {
165 int pid; /* child process id */
166 int fd_send; /* write to child here */
167 int fd_recv; /* read from child here */
168 int npending; /* # rays in process */
169 RNUMBER rno[RAYQLEN]; /* working on these rays */
170 } r_proc[MAX_NPROCS]; /* our child processes */
171
172 static RAY r_queue[2*RAYQLEN]; /* ray i/o buffer */
173 static int r_send_next = 0; /* next send ray placement */
174 static int r_recv_first = RAYQLEN; /* position of first unreported ray */
175 static int r_recv_next = RAYQLEN; /* next received ray placement */
176
177 #define sendq_full() (r_send_next >= RAYQLEN)
178
179 static int ray_pflush(void);
180 static void ray_pchild(int fd_in, int fd_out);
181
182
183 void
184 ray_pinit( /* initialize ray-tracing processes */
185 char *otnm,
186 int nproc
187 )
188 {
189 if (nobjects > 0) /* close old calculation */
190 ray_pdone(0);
191
192 ray_init(otnm); /* load the shared scene */
193
194 ray_popen(nproc); /* fork children */
195 }
196
197
198 static int
199 ray_pflush(void) /* send queued rays to idle children */
200 {
201 int nc, n, nw, i, sfirst;
202
203 if ((ray_pnidle <= 0) | (r_send_next <= 0))
204 return(0); /* nothing we can send */
205
206 sfirst = 0; /* divvy up labor */
207 nc = ray_pnidle;
208 for (i = ray_pnprocs; nc && i--; ) {
209 if (r_proc[i].npending > 0)
210 continue; /* child looks busy */
211 n = (r_send_next - sfirst)/nc--;
212 if (!n)
213 continue;
214 /* smuggle set size in crtype */
215 r_queue[sfirst].crtype = n;
216 nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
217 sizeof(RAY)*n);
218 if (nw != sizeof(RAY)*n)
219 return(-1); /* write error */
220 r_proc[i].npending = n;
221 while (n--) /* record ray IDs */
222 r_proc[i].rno[n] = r_queue[sfirst+n].rno;
223 sfirst += r_proc[i].npending;
224 ray_pnidle--; /* now she's busy */
225 }
226 if (sfirst != r_send_next)
227 error(CONSISTENCY, "code screwup in ray_pflush()");
228 r_send_next = 0;
229 return(sfirst); /* return total # sent */
230 }
231
232
233 void
234 ray_psend( /* add a ray to our send queue */
235 RAY *r
236 )
237 {
238 if (r == NULL)
239 return;
240 /* flush output if necessary */
241 if (sendq_full() && ray_pflush() <= 0)
242 error(INTERNAL, "ray_pflush failed in ray_psend()");
243
244 r_queue[r_send_next++] = *r;
245 }
246
247
248 int
249 ray_pqueue( /* queue a ray for computation */
250 RAY *r
251 )
252 {
253 if (r == NULL)
254 return(0);
255 /* check for full send queue */
256 if (sendq_full()) {
257 RAY mySend = *r;
258 /* wait for a result */
259 if (ray_presult(r, 0) <= 0)
260 return(-1);
261 /* put new ray in queue */
262 r_queue[r_send_next++] = mySend;
263 /* XXX r_send_next may now be > RAYQLEN */
264 return(1);
265 }
266 /* else add ray to send queue */
267 r_queue[r_send_next++] = *r;
268 /* check for returned ray... */
269 if (r_recv_first >= r_recv_next)
270 return(0);
271 /* ...one is sitting in queue */
272 *r = r_queue[r_recv_first++];
273 return(1);
274 }
275
276
277 int
278 ray_presult( /* check for a completed ray */
279 RAY *r,
280 int poll
281 )
282 {
283 static struct timeval tpoll; /* zero timeval struct */
284 static fd_set readset, errset;
285 int n, ok;
286 register int pn;
287
288 if (r == NULL)
289 return(0);
290 /* check queued results first */
291 if (r_recv_first < r_recv_next) {
292 *r = r_queue[r_recv_first++];
293 return(1);
294 }
295 if (poll < 0) /* immediate polling mode? */
296 return(0);
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 if (!poll && ray_pnprocs == 1) /* one process -> skip select() */
310 FD_SET(r_proc[0].fd_recv, &readset);
311
312 getready: /* any children waiting for us? */
313 for (pn = ray_pnprocs; pn--; )
314 if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
315 FD_ISSET(r_proc[pn].fd_recv, &errset))
316 break;
317 /* call select() if we must */
318 if (pn < 0) {
319 FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
320 for (pn = ray_pnprocs; pn--; ) {
321 if (r_proc[pn].npending > 0)
322 FD_SET(r_proc[pn].fd_recv, &readset);
323 FD_SET(r_proc[pn].fd_recv, &errset);
324 if (r_proc[pn].fd_recv >= n)
325 n = r_proc[pn].fd_recv + 1;
326 }
327 /* find out who is ready */
328 while ((n = select(n, &readset, (fd_set *)NULL, &errset,
329 poll ? &tpoll : (struct timeval *)NULL)) < 0)
330 if (errno != EINTR) {
331 error(WARNING,
332 "select call failed in ray_presult()");
333 ray_pclose(0);
334 return(-1);
335 }
336 if (n > 0) /* go back and get it */
337 goto getready;
338 return(0); /* else poll came up empty */
339 }
340 if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
341 error(CONSISTENCY, "buffer shortage in ray_presult()");
342
343 /* read rendered ray data */
344 n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
345 sizeof(RAY)*r_proc[pn].npending);
346 if (n > 0) {
347 r_recv_next += n/sizeof(RAY);
348 ok = (n == sizeof(RAY)*r_proc[pn].npending);
349 } else
350 ok = 0;
351 /* reset child's status */
352 FD_CLR(r_proc[pn].fd_recv, &readset);
353 if (n <= 0)
354 FD_CLR(r_proc[pn].fd_recv, &errset);
355 r_proc[pn].npending = 0;
356 ray_pnidle++;
357 /* check for rendering errors */
358 if (!ok) {
359 ray_pclose(0); /* process died -- clean up */
360 return(-1);
361 }
362 /* preen returned rays */
363 for (n = r_recv_next - r_recv_first; n--; ) {
364 register RAY *rp = &r_queue[r_recv_first + n];
365 rp->rno = r_proc[pn].rno[n];
366 rp->parent = NULL;
367 rp->newcset = rp->clipset = NULL;
368 rp->rox = NULL;
369 rp->slights = NULL;
370 }
371 /* return first ray received */
372 *r = r_queue[r_recv_first++];
373 return(1);
374 }
375
376
377 void
378 ray_pdone( /* reap children and free data */
379 int freall
380 )
381 {
382 ray_pclose(0); /* close child processes */
383
384 if (shm_boundary != NULL) { /* clear shared memory boundary */
385 free((void *)shm_boundary);
386 shm_boundary = NULL;
387 }
388
389 ray_done(freall); /* free rendering data */
390 }
391
392
393 static void
394 ray_pchild( /* process rays (never returns) */
395 int fd_in,
396 int fd_out
397 )
398 {
399 int n;
400 register int i;
401 /* flag child process for quit() */
402 ray_pnprocs = -1;
403 /* read each ray request set */
404 while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
405 int n2;
406 if (n < sizeof(RAY))
407 break;
408 /* get smuggled set length */
409 n2 = sizeof(RAY)*r_queue[0].crtype - n;
410 if (n2 < 0)
411 error(INTERNAL, "buffer over-read in ray_pchild()");
412 if (n2 > 0) { /* read the rest of the set */
413 i = readbuf(fd_in, (char *)r_queue + n, n2);
414 if (i != n2)
415 break;
416 n += n2;
417 }
418 n /= sizeof(RAY);
419 /* evaluate rays */
420 for (i = 0; i < n; i++) {
421 r_queue[i].crtype = r_queue[i].rtype;
422 r_queue[i].parent = NULL;
423 r_queue[i].clipset = NULL;
424 r_queue[i].slights = NULL;
425 r_queue[i].rlvl = 0;
426 samplendx++;
427 rayclear(&r_queue[i]);
428 rayvalue(&r_queue[i]);
429 }
430 /* write back our results */
431 i = writebuf(fd_out, (char *)r_queue, sizeof(RAY)*n);
432 if (i != sizeof(RAY)*n)
433 error(SYSTEM, "write error in ray_pchild()");
434 }
435 if (n)
436 error(SYSTEM, "read error in ray_pchild()");
437 ambsync();
438 quit(0); /* normal exit */
439 }
440
441
442 void
443 ray_popen( /* open the specified # processes */
444 int nadd
445 )
446 {
447 /* check if our table has room */
448 if (ray_pnprocs + nadd > MAX_NPROCS)
449 nadd = MAX_NPROCS - ray_pnprocs;
450 if (nadd <= 0)
451 return;
452 ambsync(); /* load any new ambient values */
453 if (shm_boundary == NULL) { /* first child process? */
454 preload_objs(); /* preload auxiliary data */
455 /* set shared memory boundary */
456 shm_boundary = (char *)malloc(16);
457 strcpy(shm_boundary, "SHM_BOUNDARY");
458 }
459 fflush(NULL); /* clear pending output */
460 while (nadd--) { /* fork each new process */
461 int p0[2], p1[2];
462 if (pipe(p0) < 0 || pipe(p1) < 0)
463 error(SYSTEM, "cannot create pipe");
464 if ((r_proc[ray_pnprocs].pid = fork()) == 0) {
465 int pn; /* close others' descriptors */
466 for (pn = ray_pnprocs; pn--; ) {
467 close(r_proc[pn].fd_send);
468 close(r_proc[pn].fd_recv);
469 }
470 close(p0[0]); close(p1[1]);
471 close(0); /* don't share stdin */
472 /* following call never returns */
473 ray_pchild(p1[0], p0[1]);
474 }
475 if (r_proc[ray_pnprocs].pid < 0)
476 error(SYSTEM, "cannot fork child process");
477 close(p1[0]); close(p0[1]);
478 /*
479 * Close write stream on exec to avoid multiprocessing deadlock.
480 * No use in read stream without it, so set flag there as well.
481 */
482 fcntl(p1[1], F_SETFD, FD_CLOEXEC);
483 fcntl(p0[0], F_SETFD, FD_CLOEXEC);
484 r_proc[ray_pnprocs].fd_send = p1[1];
485 r_proc[ray_pnprocs].fd_recv = p0[0];
486 r_proc[ray_pnprocs].npending = 0;
487 ray_pnprocs++;
488 ray_pnidle++;
489 }
490 }
491
492
493 void
494 ray_pclose( /* close one or more child processes */
495 int nsub
496 )
497 {
498 static int inclose = 0;
499 RAY res;
500 /* check recursion */
501 if (inclose)
502 return;
503 inclose++;
504 /* check argument */
505 if ((nsub <= 0) | (nsub > ray_pnprocs))
506 nsub = ray_pnprocs;
507 /* clear our ray queue */
508 while (ray_presult(&res,0) > 0)
509 ;
510 r_send_next = 0; /* hard reset in case of error */
511 r_recv_first = r_recv_next = RAYQLEN;
512 /* clean up children */
513 while (nsub--) {
514 int status;
515 ray_pnprocs--;
516 close(r_proc[ray_pnprocs].fd_send);
517 if (waitpid(r_proc[ray_pnprocs].pid, &status, 0) < 0)
518 status = 127<<8;
519 close(r_proc[ray_pnprocs].fd_recv);
520 if (status) {
521 sprintf(errmsg,
522 "rendering process %d exited with code %d",
523 r_proc[ray_pnprocs].pid, status>>8);
524 error(WARNING, errmsg);
525 }
526 ray_pnidle--;
527 }
528 inclose--;
529 }