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root/radiance/ray/src/rt/ambient.c
Revision: 2.68
Committed: Thu Oct 14 05:54:44 2010 UTC (13 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.67: +11 -17 lines
Log Message:
Fixed long-standing bug in ambient file synchronization under FreeBSD

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: ambient.c,v 2.67 2007/11/17 06:21:58 greg Exp $";
3 #endif
4 /*
5 * ambient.c - routines dealing with ambient (inter-reflected) component.
6 *
7 * Declarations of external symbols in ambient.h
8 */
9
10 #include "copyright.h"
11
12 #include <string.h>
13
14 #include "platform.h"
15 #include "ray.h"
16 #include "otypes.h"
17 #include "resolu.h"
18 #include "ambient.h"
19 #include "random.h"
20
21 #ifndef OCTSCALE
22 #define OCTSCALE 1.0 /* ceil((valid rad.)/(cube size)) */
23 #endif
24
25 extern char *shm_boundary; /* memory sharing boundary */
26
27 #ifndef MAXASET
28 #define MAXASET 4095 /* maximum number of elements in ambient set */
29 #endif
30 OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
31
32 double maxarad; /* maximum ambient radius */
33 double minarad; /* minimum ambient radius */
34
35 static AMBTREE atrunk; /* our ambient trunk node */
36
37 static FILE *ambfp = NULL; /* ambient file pointer */
38 static int nunflshed = 0; /* number of unflushed ambient values */
39
40 #ifndef SORT_THRESH
41 #ifdef SMLMEM
42 #define SORT_THRESH ((3L<<20)/sizeof(AMBVAL))
43 #else
44 #define SORT_THRESH ((9L<<20)/sizeof(AMBVAL))
45 #endif
46 #endif
47 #ifndef SORT_INTVL
48 #define SORT_INTVL (SORT_THRESH<<1)
49 #endif
50 #ifndef MAX_SORT_INTVL
51 #define MAX_SORT_INTVL (SORT_INTVL<<6)
52 #endif
53
54 static double avsum = 0.; /* computed ambient value sum (log) */
55 static unsigned int navsum = 0; /* number of values in avsum */
56 static unsigned int nambvals = 0; /* total number of indirect values */
57 static unsigned int nambshare = 0; /* number of values from file */
58 static unsigned long ambclock = 0; /* ambient access clock */
59 static unsigned long lastsort = 0; /* time of last value sort */
60 static long sortintvl = SORT_INTVL; /* time until next sort */
61 static FILE *ambinp = NULL; /* auxiliary file for input */
62 static long lastpos = -1; /* last flush position */
63
64 #define MAXACLOCK (1L<<30) /* clock turnover value */
65 /*
66 * Track access times unless we are sharing ambient values
67 * through memory on a multiprocessor, when we want to avoid
68 * claiming our own memory (copy on write). Go ahead anyway
69 * if more than two thirds of our values are unshared.
70 * Compile with -Dtracktime=0 to turn this code off.
71 */
72 #ifndef tracktime
73 #define tracktime (shm_boundary == NULL || nambvals > 3*nambshare)
74 #endif
75
76 #define AMBFLUSH (BUFSIZ/AMBVALSIZ)
77
78 #define newambval() (AMBVAL *)malloc(sizeof(AMBVAL))
79 #define freeav(av) free((void *)av);
80
81 static void initambfile(int creat);
82 static void avsave(AMBVAL *av);
83 static AMBVAL *avstore(AMBVAL *aval);
84 static AMBTREE *newambtree(void);
85 static void freeambtree(AMBTREE *atp);
86
87 typedef void unloadtf_t(void *);
88 static unloadtf_t avinsert;
89 static unloadtf_t av2list;
90 static void unloadatree(AMBTREE *at, unloadtf_t *f);
91
92 static int aposcmp(const void *avp1, const void *avp2);
93 static int avlmemi(AMBVAL *avaddr);
94 static void sortambvals(int always);
95
96 #ifdef F_SETLKW
97 static void aflock(int typ);
98 #endif
99
100
101 extern void
102 setambres( /* set ambient resolution */
103 int ar
104 )
105 {
106 ambres = ar < 0 ? 0 : ar; /* may be done already */
107 /* set min & max radii */
108 if (ar <= 0) {
109 minarad = 0;
110 maxarad = thescene.cusize / 2.0;
111 } else {
112 minarad = thescene.cusize / ar;
113 maxarad = 64 * minarad; /* heuristic */
114 if (maxarad > thescene.cusize / 2.0)
115 maxarad = thescene.cusize / 2.0;
116 }
117 if (minarad <= FTINY)
118 minarad = 10*FTINY;
119 if (maxarad <= minarad)
120 maxarad = 64 * minarad;
121 }
122
123
124 extern void
125 setambacc( /* set ambient accuracy */
126 double newa
127 )
128 {
129 double ambdiff;
130
131 if (newa < 0.0)
132 newa = 0.0;
133 ambdiff = fabs(newa - ambacc);
134 if (ambdiff >= .01 && (ambacc = newa) > FTINY && nambvals > 0)
135 sortambvals(1); /* rebuild tree */
136 }
137
138
139 extern void
140 setambient(void) /* initialize calculation */
141 {
142 int readonly = 0;
143 long flen;
144 AMBVAL amb;
145 /* make sure we're fresh */
146 ambdone();
147 /* init ambient limits */
148 setambres(ambres);
149 setambacc(ambacc);
150 if (ambfile == NULL || !ambfile[0])
151 return;
152 if (ambacc <= FTINY) {
153 sprintf(errmsg, "zero ambient accuracy so \"%s\" not opened",
154 ambfile);
155 error(WARNING, errmsg);
156 return;
157 }
158 /* open ambient file */
159 if ((ambfp = fopen(ambfile, "r+")) == NULL)
160 readonly = (ambfp = fopen(ambfile, "r")) != NULL;
161 if (ambfp != NULL) {
162 initambfile(0); /* file exists */
163 lastpos = ftell(ambfp);
164 while (readambval(&amb, ambfp))
165 avinsert(avstore(&amb));
166 nambshare = nambvals; /* share loaded values */
167 if (readonly) {
168 sprintf(errmsg,
169 "loaded %u values from read-only ambient file",
170 nambvals);
171 error(WARNING, errmsg);
172 fclose(ambfp); /* close file so no writes */
173 ambfp = NULL;
174 return; /* avoid ambsync() */
175 }
176 /* align file pointer */
177 lastpos += (long)nambvals*AMBVALSIZ;
178 flen = lseek(fileno(ambfp), (off_t)0, SEEK_END);
179 if (flen != lastpos) {
180 sprintf(errmsg,
181 "ignoring last %ld values in ambient file (corrupted)",
182 (flen - lastpos)/AMBVALSIZ);
183 error(WARNING, errmsg);
184 fseek(ambfp, lastpos, SEEK_SET);
185 #ifndef _WIN32 /* XXX we need a replacement for that one */
186 ftruncate(fileno(ambfp), (off_t)lastpos);
187 #endif
188 }
189 } else if ((ambfp = fopen(ambfile, "w+")) != NULL) {
190 initambfile(1); /* else create new file */
191 fflush(ambfp);
192 lastpos = ftell(ambfp);
193 } else {
194 sprintf(errmsg, "cannot open ambient file \"%s\"", ambfile);
195 error(SYSTEM, errmsg);
196 }
197 #ifdef F_SETLKW
198 aflock(F_UNLCK); /* release file */
199 #endif
200 }
201
202
203 extern void
204 ambdone(void) /* close ambient file and free memory */
205 {
206 if (ambfp != NULL) { /* close ambient file */
207 ambsync();
208 fclose(ambfp);
209 ambfp = NULL;
210 if (ambinp != NULL) {
211 fclose(ambinp);
212 ambinp = NULL;
213 }
214 lastpos = -1;
215 }
216 /* free ambient tree */
217 unloadatree(&atrunk, free);
218 /* reset state variables */
219 avsum = 0.;
220 navsum = 0;
221 nambvals = 0;
222 nambshare = 0;
223 ambclock = 0;
224 lastsort = 0;
225 sortintvl = SORT_INTVL;
226 }
227
228
229 extern void
230 ambnotify( /* record new modifier */
231 OBJECT obj
232 )
233 {
234 static int hitlimit = 0;
235 register OBJREC *o;
236 register char **amblp;
237
238 if (obj == OVOID) { /* starting over */
239 ambset[0] = 0;
240 hitlimit = 0;
241 return;
242 }
243 o = objptr(obj);
244 if (hitlimit || !ismodifier(o->otype))
245 return;
246 for (amblp = amblist; *amblp != NULL; amblp++)
247 if (!strcmp(o->oname, *amblp)) {
248 if (ambset[0] >= MAXASET) {
249 error(WARNING, "too many modifiers in ambient list");
250 hitlimit++;
251 return; /* should this be fatal? */
252 }
253 insertelem(ambset, obj);
254 return;
255 }
256 }
257
258
259 extern void
260 multambient( /* compute ambient component & multiply by coef. */
261 COLOR aval,
262 register RAY *r,
263 FVECT nrm
264 )
265 {
266 static int rdepth = 0; /* ambient recursion */
267 COLOR acol;
268 double d, l;
269
270 if (ambdiv <= 0) /* no ambient calculation */
271 goto dumbamb;
272 /* check number of bounces */
273 if (rdepth >= ambounce)
274 goto dumbamb;
275 /* check ambient list */
276 if (ambincl != -1 && r->ro != NULL &&
277 ambincl != inset(ambset, r->ro->omod))
278 goto dumbamb;
279
280 if (ambacc <= FTINY) { /* no ambient storage */
281 copycolor(acol, aval);
282 rdepth++;
283 d = doambient(acol, r, r->rweight, NULL, NULL);
284 rdepth--;
285 if (d <= FTINY)
286 goto dumbamb;
287 copycolor(aval, acol);
288 return;
289 }
290
291 if (tracktime) /* sort to minimize thrashing */
292 sortambvals(0);
293 /* interpolate ambient value */
294 setcolor(acol, 0.0, 0.0, 0.0);
295 d = sumambient(acol, r, nrm, rdepth,
296 &atrunk, thescene.cuorg, thescene.cusize);
297 if (d > FTINY) {
298 d = 1.0/d;
299 scalecolor(acol, d);
300 multcolor(aval, acol);
301 return;
302 }
303 rdepth++; /* need to cache new value */
304 d = makeambient(acol, r, nrm, rdepth-1);
305 rdepth--;
306 if (d > FTINY) {
307 multcolor(aval, acol); /* got new value */
308 return;
309 }
310 dumbamb: /* return global value */
311 if ((ambvwt <= 0) | (navsum == 0)) {
312 multcolor(aval, ambval);
313 return;
314 }
315 l = bright(ambval); /* average in computations */
316 if (l > FTINY) {
317 d = (log(l)*(double)ambvwt + avsum) /
318 (double)(ambvwt + navsum);
319 d = exp(d) / l;
320 scalecolor(aval, d);
321 multcolor(aval, ambval); /* apply color of ambval */
322 } else {
323 d = exp( avsum / (double)navsum );
324 scalecolor(aval, d); /* neutral color */
325 }
326 }
327
328
329 extern double
330 sumambient( /* get interpolated ambient value */
331 COLOR acol,
332 register RAY *r,
333 FVECT rn,
334 int al,
335 AMBTREE *at,
336 FVECT c0,
337 double s
338 )
339 {
340 double d, e1, e2, wt, wsum;
341 COLOR ct;
342 FVECT ck0;
343 int i;
344 register int j;
345 register AMBVAL *av;
346
347 wsum = 0.0;
348 /* do this node */
349 for (av = at->alist; av != NULL; av = av->next) {
350 double rn_dot = -2.0;
351 if (tracktime)
352 av->latick = ambclock;
353 /*
354 * Ambient level test.
355 */
356 if (av->lvl > al) /* list sorted, so this works */
357 break;
358 if (av->weight < 0.9*r->rweight)
359 continue;
360 /*
361 * Ambient radius test.
362 */
363 d = av->pos[0] - r->rop[0];
364 e1 = d * d;
365 d = av->pos[1] - r->rop[1];
366 e1 += d * d;
367 d = av->pos[2] - r->rop[2];
368 e1 += d * d;
369 e1 /= av->rad * av->rad;
370 if (e1 > ambacc*ambacc*1.21)
371 continue;
372 /*
373 * Direction test using closest normal.
374 */
375 d = DOT(av->dir, r->ron);
376 if (rn != r->ron) {
377 rn_dot = DOT(av->dir, rn);
378 if (rn_dot > 1.0-FTINY)
379 rn_dot = 1.0-FTINY;
380 if (rn_dot >= d-FTINY) {
381 d = rn_dot;
382 rn_dot = -2.0;
383 }
384 }
385 e2 = (1.0 - d) * r->rweight;
386 if (e2 < 0.0) e2 = 0.0;
387 if (e1 + e2 > ambacc*ambacc*1.21)
388 continue;
389 /*
390 * Ray behind test.
391 */
392 d = 0.0;
393 for (j = 0; j < 3; j++)
394 d += (r->rop[j] - av->pos[j]) *
395 (av->dir[j] + r->ron[j]);
396 if (d*0.5 < -minarad*ambacc-.001)
397 continue;
398 /*
399 * Jittering final test reduces image artifacts.
400 */
401 e1 = sqrt(e1);
402 e2 = sqrt(e2);
403 wt = e1 + e2;
404 if (wt > ambacc*(.9+.2*urand(9015+samplendx)))
405 continue;
406 /*
407 * Recompute directional error using perturbed normal
408 */
409 if (rn_dot > 0.0) {
410 e2 = sqrt((1.0 - rn_dot)*r->rweight);
411 wt = e1 + e2;
412 }
413 if (wt <= 1e-3)
414 wt = 1e3;
415 else
416 wt = 1.0 / wt;
417 wsum += wt;
418 extambient(ct, av, r->rop, rn);
419 scalecolor(ct, wt);
420 addcolor(acol, ct);
421 }
422 if (at->kid == NULL)
423 return(wsum);
424 /* do children */
425 s *= 0.5;
426 for (i = 0; i < 8; i++) {
427 for (j = 0; j < 3; j++) {
428 ck0[j] = c0[j];
429 if (1<<j & i)
430 ck0[j] += s;
431 if (r->rop[j] < ck0[j] - OCTSCALE*s)
432 break;
433 if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
434 break;
435 }
436 if (j == 3)
437 wsum += sumambient(acol, r, rn, al,
438 at->kid+i, ck0, s);
439 }
440 return(wsum);
441 }
442
443
444 extern double
445 makeambient( /* make a new ambient value for storage */
446 COLOR acol,
447 RAY *r,
448 FVECT rn,
449 int al
450 )
451 {
452 AMBVAL amb;
453 FVECT gp, gd;
454 int i;
455
456 amb.weight = 1.0; /* compute weight */
457 for (i = al; i-- > 0; )
458 amb.weight *= AVGREFL;
459 if (r->rweight < 0.1*amb.weight) /* heuristic override */
460 amb.weight = 1.25*r->rweight;
461 setcolor(acol, AVGREFL, AVGREFL, AVGREFL);
462 /* compute ambient */
463 amb.rad = doambient(acol, r, amb.weight, gp, gd);
464 if (amb.rad <= FTINY) {
465 setcolor(acol, 0.0, 0.0, 0.0);
466 return(0.0);
467 }
468 scalecolor(acol, 1./AVGREFL); /* undo assumed reflectance */
469 /* store value */
470 VCOPY(amb.pos, r->rop);
471 VCOPY(amb.dir, r->ron);
472 amb.lvl = al;
473 copycolor(amb.val, acol);
474 VCOPY(amb.gpos, gp);
475 VCOPY(amb.gdir, gd);
476 /* insert into tree */
477 avsave(&amb); /* and save to file */
478 if (rn != r->ron)
479 extambient(acol, &amb, r->rop, rn); /* texture */
480 return(amb.rad);
481 }
482
483
484 extern void
485 extambient( /* extrapolate value at pv, nv */
486 COLOR cr,
487 register AMBVAL *ap,
488 FVECT pv,
489 FVECT nv
490 )
491 {
492 FVECT v1;
493 register int i;
494 double d;
495
496 d = 1.0; /* zeroeth order */
497 /* gradient due to translation */
498 for (i = 0; i < 3; i++)
499 d += ap->gpos[i]*(pv[i]-ap->pos[i]);
500 /* gradient due to rotation */
501 VCROSS(v1, ap->dir, nv);
502 d += DOT(ap->gdir, v1);
503 if (d <= 0.0) {
504 setcolor(cr, 0.0, 0.0, 0.0);
505 return;
506 }
507 copycolor(cr, ap->val);
508 scalecolor(cr, d);
509 }
510
511
512 static void
513 initambfile( /* initialize ambient file */
514 int cre8
515 )
516 {
517 extern char *progname, *octname;
518 static char *mybuf = NULL;
519
520 #ifdef F_SETLKW
521 aflock(creat ? F_WRLCK : F_RDLCK);
522 #endif
523 SET_FILE_BINARY(ambfp);
524 if (mybuf == NULL)
525 mybuf = (char *)bmalloc(BUFSIZ+8);
526 setbuf(ambfp, mybuf);
527 if (cre8) { /* new file */
528 newheader("RADIANCE", ambfp);
529 fprintf(ambfp, "%s -av %g %g %g -aw %d -ab %d -aa %g ",
530 progname, colval(ambval,RED),
531 colval(ambval,GRN), colval(ambval,BLU),
532 ambvwt, ambounce, ambacc);
533 fprintf(ambfp, "-ad %d -as %d -ar %d ",
534 ambdiv, ambssamp, ambres);
535 if (octname != NULL)
536 fputs(octname, ambfp);
537 fputc('\n', ambfp);
538 fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
539 fputnow(ambfp);
540 fputformat(AMBFMT, ambfp);
541 fputc('\n', ambfp);
542 putambmagic(ambfp);
543 } else if (checkheader(ambfp, AMBFMT, NULL) < 0 || !hasambmagic(ambfp))
544 error(USER, "bad ambient file");
545 }
546
547
548 static void
549 avsave( /* insert and save an ambient value */
550 AMBVAL *av
551 )
552 {
553 avinsert(avstore(av));
554 if (ambfp == NULL)
555 return;
556 if (writambval(av, ambfp) < 0)
557 goto writerr;
558 if (++nunflshed >= AMBFLUSH)
559 if (ambsync() == EOF)
560 goto writerr;
561 return;
562 writerr:
563 error(SYSTEM, "error writing to ambient file");
564 }
565
566
567 static AMBVAL *
568 avstore( /* allocate memory and store aval */
569 register AMBVAL *aval
570 )
571 {
572 register AMBVAL *av;
573 double d;
574
575 if ((av = newambval()) == NULL)
576 error(SYSTEM, "out of memory in avstore");
577 *av = *aval;
578 av->latick = ambclock;
579 av->next = NULL;
580 nambvals++;
581 d = bright(av->val);
582 if (d > FTINY) { /* add to log sum for averaging */
583 avsum += log(d);
584 navsum++;
585 }
586 return(av);
587 }
588
589
590 #define ATALLOCSZ 512 /* #/8 trees to allocate at once */
591
592 static AMBTREE *atfreelist = NULL; /* free ambient tree structures */
593
594
595 static AMBTREE *
596 newambtree(void) /* allocate 8 ambient tree structs */
597 {
598 register AMBTREE *atp, *upperlim;
599
600 if (atfreelist == NULL) { /* get more nodes */
601 atfreelist = (AMBTREE *)malloc(ATALLOCSZ*8*sizeof(AMBTREE));
602 if (atfreelist == NULL)
603 return(NULL);
604 /* link new free list */
605 upperlim = atfreelist + 8*(ATALLOCSZ-1);
606 for (atp = atfreelist; atp < upperlim; atp += 8)
607 atp->kid = atp + 8;
608 atp->kid = NULL;
609 }
610 atp = atfreelist;
611 atfreelist = atp->kid;
612 memset((char *)atp, '\0', 8*sizeof(AMBTREE));
613 return(atp);
614 }
615
616
617 static void
618 freeambtree( /* free 8 ambient tree structs */
619 AMBTREE *atp
620 )
621 {
622 atp->kid = atfreelist;
623 atfreelist = atp;
624 }
625
626
627 static void
628 avinsert( /* insert ambient value in our tree */
629 void *av
630 )
631 {
632 register AMBTREE *at;
633 register AMBVAL *ap;
634 AMBVAL avh;
635 FVECT ck0;
636 double s;
637 int branch;
638 register int i;
639
640 if (((AMBVAL*)av)->rad <= FTINY)
641 error(CONSISTENCY, "zero ambient radius in avinsert");
642 at = &atrunk;
643 VCOPY(ck0, thescene.cuorg);
644 s = thescene.cusize;
645 while (s*(OCTSCALE/2) > ((AMBVAL*)av)->rad*ambacc) {
646 if (at->kid == NULL)
647 if ((at->kid = newambtree()) == NULL)
648 error(SYSTEM, "out of memory in avinsert");
649 s *= 0.5;
650 branch = 0;
651 for (i = 0; i < 3; i++)
652 if (((AMBVAL*)av)->pos[i] > ck0[i] + s) {
653 ck0[i] += s;
654 branch |= 1 << i;
655 }
656 at = at->kid + branch;
657 }
658 avh.next = at->alist; /* order by increasing level */
659 for (ap = &avh; ap->next != NULL; ap = ap->next)
660 if (ap->next->lvl >= ((AMBVAL*)av)->lvl)
661 break;
662 ((AMBVAL*)av)->next = ap->next;
663 ap->next = (AMBVAL*)av;
664 at->alist = avh.next;
665 }
666
667
668 static void
669 unloadatree( /* unload an ambient value tree */
670 register AMBTREE *at,
671 unloadtf_t *f
672 )
673 {
674 register AMBVAL *av;
675 register int i;
676 /* transfer values at this node */
677 for (av = at->alist; av != NULL; av = at->alist) {
678 at->alist = av->next;
679 (*f)(av);
680 }
681 if (at->kid == NULL)
682 return;
683 for (i = 0; i < 8; i++) /* transfer and free children */
684 unloadatree(at->kid+i, f);
685 freeambtree(at->kid);
686 at->kid = NULL;
687 }
688
689
690 static struct avl {
691 AMBVAL *p;
692 unsigned long t;
693 } *avlist1; /* ambient value list with ticks */
694 static AMBVAL **avlist2; /* memory positions for sorting */
695 static int i_avlist; /* index for lists */
696
697 static int alatcmp(const void *av1, const void *av2);
698
699 static void
700 av2list(
701 void *av
702 )
703 {
704 #ifdef DEBUG
705 if (i_avlist >= nambvals)
706 error(CONSISTENCY, "too many ambient values in av2list1");
707 #endif
708 avlist1[i_avlist].p = avlist2[i_avlist] = (AMBVAL*)av;
709 avlist1[i_avlist++].t = ((AMBVAL*)av)->latick;
710 }
711
712
713 static int
714 alatcmp( /* compare ambient values for MRA */
715 const void *av1,
716 const void *av2
717 )
718 {
719 register long lc = ((struct avl *)av2)->t - ((struct avl *)av1)->t;
720 return(lc<0 ? -1 : lc>0 ? 1 : 0);
721 }
722
723
724 /* GW NOTE 2002/10/3:
725 * I used to compare AMBVAL pointers, but found that this was the
726 * cause of a serious consistency error with gcc, since the optimizer
727 * uses some dangerous trick in pointer subtraction that
728 * assumes pointers differ by exact struct size increments.
729 */
730 static int
731 aposcmp( /* compare ambient value positions */
732 const void *avp1,
733 const void *avp2
734 )
735 {
736 register long diff = *(char * const *)avp1 - *(char * const *)avp2;
737 if (diff < 0)
738 return(-1);
739 return(diff > 0);
740 }
741
742 #if 1
743 static int
744 avlmemi( /* find list position from address */
745 AMBVAL *avaddr
746 )
747 {
748 register AMBVAL **avlpp;
749
750 avlpp = (AMBVAL **)bsearch((char *)&avaddr, (char *)avlist2,
751 nambvals, sizeof(AMBVAL *), aposcmp);
752 if (avlpp == NULL)
753 error(CONSISTENCY, "address not found in avlmemi");
754 return(avlpp - avlist2);
755 }
756 #else
757 #define avlmemi(avaddr) ((AMBVAL **)bsearch((char *)&avaddr,(char *)avlist2, \
758 nambvals,sizeof(AMBVAL *),aposcmp) - avlist2)
759 #endif
760
761
762 static void
763 sortambvals( /* resort ambient values */
764 int always
765 )
766 {
767 AMBTREE oldatrunk;
768 AMBVAL tav, *tap, *pnext;
769 register int i, j;
770 /* see if it's time yet */
771 if (!always && (ambclock++ < lastsort+sortintvl ||
772 nambvals < SORT_THRESH))
773 return;
774 /*
775 * The idea here is to minimize memory thrashing
776 * in VM systems by improving reference locality.
777 * We do this by periodically sorting our stored ambient
778 * values in memory in order of most recently to least
779 * recently accessed. This ordering was chosen so that new
780 * ambient values (which tend to be less important) go into
781 * higher memory with the infrequently accessed values.
782 * Since we expect our values to need sorting less
783 * frequently as the process continues, we double our
784 * waiting interval after each call.
785 * This routine is also called by setambacc() with
786 * the "always" parameter set to 1 so that the ambient
787 * tree will be rebuilt with the new accuracy parameter.
788 */
789 if (tracktime) { /* allocate pointer arrays to sort */
790 avlist2 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
791 avlist1 = (struct avl *)malloc(nambvals*sizeof(struct avl));
792 } else {
793 avlist2 = NULL;
794 avlist1 = NULL;
795 }
796 if (avlist1 == NULL) { /* no time tracking -- rebuild tree? */
797 if (avlist2 != NULL)
798 free((void *)avlist2);
799 if (always) { /* rebuild without sorting */
800 oldatrunk = atrunk;
801 atrunk.alist = NULL;
802 atrunk.kid = NULL;
803 unloadatree(&oldatrunk, avinsert);
804 }
805 } else { /* sort memory by last access time */
806 /*
807 * Sorting memory is tricky because it isn't contiguous.
808 * We have to sort an array of pointers by MRA and also
809 * by memory position. We then copy values in "loops"
810 * to minimize memory hits. Nevertheless, we will visit
811 * everyone at least twice, and this is an expensive process
812 * when we're thrashing, which is when we need to do it.
813 */
814 #ifdef DEBUG
815 sprintf(errmsg, "sorting %u ambient values at ambclock=%lu...",
816 nambvals, ambclock);
817 eputs(errmsg);
818 #endif
819 i_avlist = 0;
820 unloadatree(&atrunk, av2list); /* empty current tree */
821 #ifdef DEBUG
822 if (i_avlist < nambvals)
823 error(CONSISTENCY, "missing ambient values in sortambvals");
824 #endif
825 qsort((char *)avlist1, nambvals, sizeof(struct avl), alatcmp);
826 qsort((char *)avlist2, nambvals, sizeof(AMBVAL *), aposcmp);
827 for (i = 0; i < nambvals; i++) {
828 if (avlist1[i].p == NULL)
829 continue;
830 tap = avlist2[i];
831 tav = *tap;
832 for (j = i; (pnext = avlist1[j].p) != tap;
833 j = avlmemi(pnext)) {
834 *(avlist2[j]) = *pnext;
835 avinsert(avlist2[j]);
836 avlist1[j].p = NULL;
837 }
838 *(avlist2[j]) = tav;
839 avinsert(avlist2[j]);
840 avlist1[j].p = NULL;
841 }
842 free((void *)avlist1);
843 free((void *)avlist2);
844 /* compute new sort interval */
845 sortintvl = ambclock - lastsort;
846 if (sortintvl >= MAX_SORT_INTVL/2)
847 sortintvl = MAX_SORT_INTVL;
848 else
849 sortintvl <<= 1; /* wait twice as long next */
850 #ifdef DEBUG
851 eputs("done\n");
852 #endif
853 }
854 if (ambclock >= MAXACLOCK)
855 ambclock = MAXACLOCK/2;
856 lastsort = ambclock;
857 }
858
859
860 #ifdef F_SETLKW
861
862 static void
863 aflock( /* lock/unlock ambient file */
864 int typ
865 )
866 {
867 static struct flock fls; /* static so initialized to zeroes */
868
869 if (typ == fls.l_type) /* already called? */
870 return;
871 fls.l_type = typ;
872 if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
873 error(SYSTEM, "cannot (un)lock ambient file");
874 }
875
876
877 extern int
878 ambsync(void) /* synchronize ambient file */
879 {
880 long flen;
881 AMBVAL avs;
882 register int n;
883
884 if (ambfp == NULL) /* no ambient file? */
885 return(0);
886 /* gain appropriate access */
887 aflock(nunflshed ? F_WRLCK : F_RDLCK);
888 /* see if file has grown */
889 if ((flen = lseek(fileno(ambfp), (off_t)0, SEEK_END)) < 0)
890 goto seekerr;
891 if ((n = flen - lastpos) > 0) { /* file has grown */
892 if (ambinp == NULL) { /* use duplicate filedes */
893 ambinp = fdopen(dup(fileno(ambfp)), "r");
894 if (ambinp == NULL)
895 error(SYSTEM, "fdopen failed in ambsync");
896 }
897 if (fseek(ambinp, lastpos, SEEK_SET) < 0)
898 goto seekerr;
899 while (n >= AMBVALSIZ) { /* load contributed values */
900 if (!readambval(&avs, ambinp)) {
901 sprintf(errmsg,
902 "ambient file \"%s\" corrupted near character %ld",
903 ambfile, flen - n);
904 error(WARNING, errmsg);
905 break;
906 }
907 avinsert(avstore(&avs));
908 n -= AMBVALSIZ;
909 }
910 lastpos = flen - n;
911 /*** seek always as safety measure
912 if (n) ***/ /* alignment */
913 if (lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
914 goto seekerr;
915 }
916 n = fflush(ambfp); /* calls write() at last */
917 if (n != EOF)
918 lastpos += (long)nunflshed*AMBVALSIZ;
919 else if ((lastpos = lseek(fileno(ambfp), (off_t)0, SEEK_CUR)) < 0)
920 goto seekerr;
921
922 aflock(F_UNLCK); /* release file */
923 nunflshed = 0;
924 return(n);
925 seekerr:
926 error(SYSTEM, "seek failed in ambsync");
927 return -1; /* pro forma return */
928 }
929
930 #else
931
932 extern int
933 ambsync(void) /* flush ambient file */
934 {
935 if (ambfp == NULL)
936 return(0);
937 nunflshed = 0;
938 return(fflush(ambfp));
939 }
940
941 #endif