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root/radiance/ray/src/rt/ambient.c
Revision: 2.70
Committed: Thu Sep 22 02:15:56 2011 UTC (12 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R1
Changes since 2.69: +28 -32 lines
Log Message:
Minor optimizations

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: ambient.c,v 2.69 2011/06/27 22:10:37 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 OBJREC *o;
236 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 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 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 int j;
345 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 VSUB(ck0, av->pos, r->rop);
364 e1 = DOT(ck0, ck0) / (av->rad * av->rad);
365 if (e1 > ambacc*ambacc*1.21)
366 continue;
367 /*
368 * Direction test using closest normal.
369 */
370 d = DOT(av->dir, r->ron);
371 if (rn != r->ron) {
372 rn_dot = DOT(av->dir, rn);
373 if (rn_dot > 1.0-FTINY)
374 rn_dot = 1.0-FTINY;
375 if (rn_dot >= d-FTINY) {
376 d = rn_dot;
377 rn_dot = -2.0;
378 }
379 }
380 e2 = (1.0 - d) * r->rweight;
381 if (e2 < 0.0)
382 e2 = 0.0;
383 else if (e1 + e2 > ambacc*ambacc*1.21)
384 continue;
385 /*
386 * Ray behind test.
387 */
388 d = 0.0;
389 for (j = 0; j < 3; j++)
390 d += (r->rop[j] - av->pos[j]) *
391 (av->dir[j] + r->ron[j]);
392 if (d*0.5 < -minarad*ambacc-.001)
393 continue;
394 /*
395 * Jittering final test reduces image artifacts.
396 */
397 e1 = sqrt(e1);
398 e2 = sqrt(e2);
399 wt = e1 + e2;
400 if (wt > ambacc*(.9+.2*urand(9015+samplendx)))
401 continue;
402 /*
403 * Recompute directional error using perturbed normal
404 */
405 if (rn_dot > 0.0) {
406 e2 = sqrt((1.0 - rn_dot)*r->rweight);
407 wt = e1 + e2;
408 }
409 if (wt <= 1e-3)
410 wt = 1e3;
411 else
412 wt = 1.0 / wt;
413 wsum += wt;
414 extambient(ct, av, r->rop, rn);
415 scalecolor(ct, wt);
416 addcolor(acol, ct);
417 }
418 if (at->kid == NULL)
419 return(wsum);
420 /* do children */
421 s *= 0.5;
422 for (i = 0; i < 8; i++) {
423 for (j = 0; j < 3; j++) {
424 ck0[j] = c0[j];
425 if (1<<j & i)
426 ck0[j] += s;
427 if (r->rop[j] < ck0[j] - OCTSCALE*s)
428 break;
429 if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
430 break;
431 }
432 if (j == 3)
433 wsum += sumambient(acol, r, rn, al,
434 at->kid+i, ck0, s);
435 }
436 return(wsum);
437 }
438
439
440 extern double
441 makeambient( /* make a new ambient value for storage */
442 COLOR acol,
443 RAY *r,
444 FVECT rn,
445 int al
446 )
447 {
448 AMBVAL amb;
449 FVECT gp, gd;
450 int i;
451
452 amb.weight = 1.0; /* compute weight */
453 for (i = al; i-- > 0; )
454 amb.weight *= AVGREFL;
455 if (r->rweight < 0.1*amb.weight) /* heuristic override */
456 amb.weight = 1.25*r->rweight;
457 setcolor(acol, AVGREFL, AVGREFL, AVGREFL);
458 /* compute ambient */
459 amb.rad = doambient(acol, r, amb.weight, gp, gd);
460 if (amb.rad <= FTINY) {
461 setcolor(acol, 0.0, 0.0, 0.0);
462 return(0.0);
463 }
464 scalecolor(acol, 1./AVGREFL); /* undo assumed reflectance */
465 /* store value */
466 VCOPY(amb.pos, r->rop);
467 VCOPY(amb.dir, r->ron);
468 amb.lvl = al;
469 copycolor(amb.val, acol);
470 VCOPY(amb.gpos, gp);
471 VCOPY(amb.gdir, gd);
472 /* insert into tree */
473 avsave(&amb); /* and save to file */
474 if (rn != r->ron)
475 extambient(acol, &amb, r->rop, rn); /* texture */
476 return(amb.rad);
477 }
478
479
480 extern void
481 extambient( /* extrapolate value at pv, nv */
482 COLOR cr,
483 AMBVAL *ap,
484 FVECT pv,
485 FVECT nv
486 )
487 {
488 FVECT v1;
489 int i;
490 double d;
491
492 d = 1.0; /* zeroeth order */
493 /* gradient due to translation */
494 for (i = 0; i < 3; i++)
495 d += ap->gpos[i]*(pv[i]-ap->pos[i]);
496 /* gradient due to rotation */
497 VCROSS(v1, ap->dir, nv);
498 d += DOT(ap->gdir, v1);
499 if (d <= 0.0) {
500 setcolor(cr, 0.0, 0.0, 0.0);
501 return;
502 }
503 copycolor(cr, ap->val);
504 scalecolor(cr, d);
505 }
506
507
508 static void
509 initambfile( /* initialize ambient file */
510 int cre8
511 )
512 {
513 extern char *progname, *octname;
514 static char *mybuf = NULL;
515
516 #ifdef F_SETLKW
517 aflock(cre8 ? F_WRLCK : F_RDLCK);
518 #endif
519 SET_FILE_BINARY(ambfp);
520 if (mybuf == NULL)
521 mybuf = (char *)bmalloc(BUFSIZ+8);
522 setbuf(ambfp, mybuf);
523 if (cre8) { /* new file */
524 newheader("RADIANCE", ambfp);
525 fprintf(ambfp, "%s -av %g %g %g -aw %d -ab %d -aa %g ",
526 progname, colval(ambval,RED),
527 colval(ambval,GRN), colval(ambval,BLU),
528 ambvwt, ambounce, ambacc);
529 fprintf(ambfp, "-ad %d -as %d -ar %d ",
530 ambdiv, ambssamp, ambres);
531 if (octname != NULL)
532 fputs(octname, ambfp);
533 fputc('\n', ambfp);
534 fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
535 fputnow(ambfp);
536 fputformat(AMBFMT, ambfp);
537 fputc('\n', ambfp);
538 putambmagic(ambfp);
539 } else if (checkheader(ambfp, AMBFMT, NULL) < 0 || !hasambmagic(ambfp))
540 error(USER, "bad ambient file");
541 }
542
543
544 static void
545 avsave( /* insert and save an ambient value */
546 AMBVAL *av
547 )
548 {
549 avinsert(avstore(av));
550 if (ambfp == NULL)
551 return;
552 if (writambval(av, ambfp) < 0)
553 goto writerr;
554 if (++nunflshed >= AMBFLUSH)
555 if (ambsync() == EOF)
556 goto writerr;
557 return;
558 writerr:
559 error(SYSTEM, "error writing to ambient file");
560 }
561
562
563 static AMBVAL *
564 avstore( /* allocate memory and store aval */
565 AMBVAL *aval
566 )
567 {
568 AMBVAL *av;
569 double d;
570
571 if ((av = newambval()) == NULL)
572 error(SYSTEM, "out of memory in avstore");
573 *av = *aval;
574 av->latick = ambclock;
575 av->next = NULL;
576 nambvals++;
577 d = bright(av->val);
578 if (d > FTINY) { /* add to log sum for averaging */
579 avsum += log(d);
580 navsum++;
581 }
582 return(av);
583 }
584
585
586 #define ATALLOCSZ 512 /* #/8 trees to allocate at once */
587
588 static AMBTREE *atfreelist = NULL; /* free ambient tree structures */
589
590
591 static AMBTREE *
592 newambtree(void) /* allocate 8 ambient tree structs */
593 {
594 AMBTREE *atp, *upperlim;
595
596 if (atfreelist == NULL) { /* get more nodes */
597 atfreelist = (AMBTREE *)malloc(ATALLOCSZ*8*sizeof(AMBTREE));
598 if (atfreelist == NULL)
599 return(NULL);
600 /* link new free list */
601 upperlim = atfreelist + 8*(ATALLOCSZ-1);
602 for (atp = atfreelist; atp < upperlim; atp += 8)
603 atp->kid = atp + 8;
604 atp->kid = NULL;
605 }
606 atp = atfreelist;
607 atfreelist = atp->kid;
608 memset((char *)atp, '\0', 8*sizeof(AMBTREE));
609 return(atp);
610 }
611
612
613 static void
614 freeambtree( /* free 8 ambient tree structs */
615 AMBTREE *atp
616 )
617 {
618 atp->kid = atfreelist;
619 atfreelist = atp;
620 }
621
622
623 static void
624 avinsert( /* insert ambient value in our tree */
625 void *av
626 )
627 {
628 AMBTREE *at;
629 AMBVAL *ap;
630 AMBVAL avh;
631 FVECT ck0;
632 double s;
633 int branch;
634 int i;
635
636 if (((AMBVAL*)av)->rad <= FTINY)
637 error(CONSISTENCY, "zero ambient radius in avinsert");
638 at = &atrunk;
639 VCOPY(ck0, thescene.cuorg);
640 s = thescene.cusize;
641 while (s*(OCTSCALE/2) > ((AMBVAL*)av)->rad*ambacc) {
642 if (at->kid == NULL)
643 if ((at->kid = newambtree()) == NULL)
644 error(SYSTEM, "out of memory in avinsert");
645 s *= 0.5;
646 branch = 0;
647 for (i = 0; i < 3; i++)
648 if (((AMBVAL*)av)->pos[i] > ck0[i] + s) {
649 ck0[i] += s;
650 branch |= 1 << i;
651 }
652 at = at->kid + branch;
653 }
654 avh.next = at->alist; /* order by increasing level */
655 for (ap = &avh; ap->next != NULL; ap = ap->next)
656 if (ap->next->lvl >= ((AMBVAL*)av)->lvl)
657 break;
658 ((AMBVAL*)av)->next = ap->next;
659 ap->next = (AMBVAL*)av;
660 at->alist = avh.next;
661 }
662
663
664 static void
665 unloadatree( /* unload an ambient value tree */
666 AMBTREE *at,
667 unloadtf_t *f
668 )
669 {
670 AMBVAL *av;
671 int i;
672 /* transfer values at this node */
673 for (av = at->alist; av != NULL; av = at->alist) {
674 at->alist = av->next;
675 (*f)(av);
676 }
677 if (at->kid == NULL)
678 return;
679 for (i = 0; i < 8; i++) /* transfer and free children */
680 unloadatree(at->kid+i, f);
681 freeambtree(at->kid);
682 at->kid = NULL;
683 }
684
685
686 static struct avl {
687 AMBVAL *p;
688 unsigned long t;
689 } *avlist1; /* ambient value list with ticks */
690 static AMBVAL **avlist2; /* memory positions for sorting */
691 static int i_avlist; /* index for lists */
692
693 static int alatcmp(const void *av1, const void *av2);
694
695 static void
696 av2list(
697 void *av
698 )
699 {
700 #ifdef DEBUG
701 if (i_avlist >= nambvals)
702 error(CONSISTENCY, "too many ambient values in av2list1");
703 #endif
704 avlist1[i_avlist].p = avlist2[i_avlist] = (AMBVAL*)av;
705 avlist1[i_avlist++].t = ((AMBVAL*)av)->latick;
706 }
707
708
709 static int
710 alatcmp( /* compare ambient values for MRA */
711 const void *av1,
712 const void *av2
713 )
714 {
715 long lc = ((struct avl *)av2)->t - ((struct avl *)av1)->t;
716 return(lc<0 ? -1 : lc>0 ? 1 : 0);
717 }
718
719
720 /* GW NOTE 2002/10/3:
721 * I used to compare AMBVAL pointers, but found that this was the
722 * cause of a serious consistency error with gcc, since the optimizer
723 * uses some dangerous trick in pointer subtraction that
724 * assumes pointers differ by exact struct size increments.
725 */
726 static int
727 aposcmp( /* compare ambient value positions */
728 const void *avp1,
729 const void *avp2
730 )
731 {
732 long diff = *(char * const *)avp1 - *(char * const *)avp2;
733 if (diff < 0)
734 return(-1);
735 return(diff > 0);
736 }
737
738 #if 1
739 static int
740 avlmemi( /* find list position from address */
741 AMBVAL *avaddr
742 )
743 {
744 AMBVAL **avlpp;
745
746 avlpp = (AMBVAL **)bsearch((char *)&avaddr, (char *)avlist2,
747 nambvals, sizeof(AMBVAL *), aposcmp);
748 if (avlpp == NULL)
749 error(CONSISTENCY, "address not found in avlmemi");
750 return(avlpp - avlist2);
751 }
752 #else
753 #define avlmemi(avaddr) ((AMBVAL **)bsearch((char *)&avaddr,(char *)avlist2, \
754 nambvals,sizeof(AMBVAL *),aposcmp) - avlist2)
755 #endif
756
757
758 static void
759 sortambvals( /* resort ambient values */
760 int always
761 )
762 {
763 AMBTREE oldatrunk;
764 AMBVAL tav, *tap, *pnext;
765 int i, j;
766 /* see if it's time yet */
767 if (!always && (ambclock++ < lastsort+sortintvl ||
768 nambvals < SORT_THRESH))
769 return;
770 /*
771 * The idea here is to minimize memory thrashing
772 * in VM systems by improving reference locality.
773 * We do this by periodically sorting our stored ambient
774 * values in memory in order of most recently to least
775 * recently accessed. This ordering was chosen so that new
776 * ambient values (which tend to be less important) go into
777 * higher memory with the infrequently accessed values.
778 * Since we expect our values to need sorting less
779 * frequently as the process continues, we double our
780 * waiting interval after each call.
781 * This routine is also called by setambacc() with
782 * the "always" parameter set to 1 so that the ambient
783 * tree will be rebuilt with the new accuracy parameter.
784 */
785 if (tracktime) { /* allocate pointer arrays to sort */
786 avlist2 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
787 avlist1 = (struct avl *)malloc(nambvals*sizeof(struct avl));
788 } else {
789 avlist2 = NULL;
790 avlist1 = NULL;
791 }
792 if (avlist1 == NULL) { /* no time tracking -- rebuild tree? */
793 if (avlist2 != NULL)
794 free((void *)avlist2);
795 if (always) { /* rebuild without sorting */
796 oldatrunk = atrunk;
797 atrunk.alist = NULL;
798 atrunk.kid = NULL;
799 unloadatree(&oldatrunk, avinsert);
800 }
801 } else { /* sort memory by last access time */
802 /*
803 * Sorting memory is tricky because it isn't contiguous.
804 * We have to sort an array of pointers by MRA and also
805 * by memory position. We then copy values in "loops"
806 * to minimize memory hits. Nevertheless, we will visit
807 * everyone at least twice, and this is an expensive process
808 * when we're thrashing, which is when we need to do it.
809 */
810 #ifdef DEBUG
811 sprintf(errmsg, "sorting %u ambient values at ambclock=%lu...",
812 nambvals, ambclock);
813 eputs(errmsg);
814 #endif
815 i_avlist = 0;
816 unloadatree(&atrunk, av2list); /* empty current tree */
817 #ifdef DEBUG
818 if (i_avlist < nambvals)
819 error(CONSISTENCY, "missing ambient values in sortambvals");
820 #endif
821 qsort((char *)avlist1, nambvals, sizeof(struct avl), alatcmp);
822 qsort((char *)avlist2, nambvals, sizeof(AMBVAL *), aposcmp);
823 for (i = 0; i < nambvals; i++) {
824 if (avlist1[i].p == NULL)
825 continue;
826 tap = avlist2[i];
827 tav = *tap;
828 for (j = i; (pnext = avlist1[j].p) != tap;
829 j = avlmemi(pnext)) {
830 *(avlist2[j]) = *pnext;
831 avinsert(avlist2[j]);
832 avlist1[j].p = NULL;
833 }
834 *(avlist2[j]) = tav;
835 avinsert(avlist2[j]);
836 avlist1[j].p = NULL;
837 }
838 free((void *)avlist1);
839 free((void *)avlist2);
840 /* compute new sort interval */
841 sortintvl = ambclock - lastsort;
842 if (sortintvl >= MAX_SORT_INTVL/2)
843 sortintvl = MAX_SORT_INTVL;
844 else
845 sortintvl <<= 1; /* wait twice as long next */
846 #ifdef DEBUG
847 eputs("done\n");
848 #endif
849 }
850 if (ambclock >= MAXACLOCK)
851 ambclock = MAXACLOCK/2;
852 lastsort = ambclock;
853 }
854
855
856 #ifdef F_SETLKW
857
858 static void
859 aflock( /* lock/unlock ambient file */
860 int typ
861 )
862 {
863 static struct flock fls; /* static so initialized to zeroes */
864
865 if (typ == fls.l_type) /* already called? */
866 return;
867 fls.l_type = typ;
868 if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
869 error(SYSTEM, "cannot (un)lock ambient file");
870 }
871
872
873 extern int
874 ambsync(void) /* synchronize ambient file */
875 {
876 long flen;
877 AMBVAL avs;
878 int n;
879
880 if (ambfp == NULL) /* no ambient file? */
881 return(0);
882 /* gain appropriate access */
883 aflock(nunflshed ? F_WRLCK : F_RDLCK);
884 /* see if file has grown */
885 if ((flen = lseek(fileno(ambfp), (off_t)0, SEEK_END)) < 0)
886 goto seekerr;
887 if ((n = flen - lastpos) > 0) { /* file has grown */
888 if (ambinp == NULL) { /* use duplicate filedes */
889 ambinp = fdopen(dup(fileno(ambfp)), "r");
890 if (ambinp == NULL)
891 error(SYSTEM, "fdopen failed in ambsync");
892 }
893 if (fseek(ambinp, lastpos, SEEK_SET) < 0)
894 goto seekerr;
895 while (n >= AMBVALSIZ) { /* load contributed values */
896 if (!readambval(&avs, ambinp)) {
897 sprintf(errmsg,
898 "ambient file \"%s\" corrupted near character %ld",
899 ambfile, flen - n);
900 error(WARNING, errmsg);
901 break;
902 }
903 avinsert(avstore(&avs));
904 n -= AMBVALSIZ;
905 }
906 lastpos = flen - n;
907 /*** seek always as safety measure
908 if (n) ***/ /* alignment */
909 if (lseek(fileno(ambfp), (off_t)lastpos, SEEK_SET) < 0)
910 goto seekerr;
911 }
912 n = fflush(ambfp); /* calls write() at last */
913 if (n != EOF)
914 lastpos += (long)nunflshed*AMBVALSIZ;
915 else if ((lastpos = lseek(fileno(ambfp), (off_t)0, SEEK_CUR)) < 0)
916 goto seekerr;
917
918 aflock(F_UNLCK); /* release file */
919 nunflshed = 0;
920 return(n);
921 seekerr:
922 error(SYSTEM, "seek failed in ambsync");
923 return -1; /* pro forma return */
924 }
925
926 #else
927
928 extern int
929 ambsync(void) /* flush ambient file */
930 {
931 if (ambfp == NULL)
932 return(0);
933 nunflshed = 0;
934 return(fflush(ambfp));
935 }
936
937 #endif