src/rt/rayfifo.c

#ifndef lint
static const char RCSid[] = "$Id: rayfifo.c,v 2.3 2009/12/12 23:08:13 greg Exp $";
#endif
/*
 *  rayfifo.c - parallelize ray queue that respects order
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

/*
 *  These routines are essentially an adjunct to raypcalls.c, providing
 *  a convenient means to get first-in/first-out behavior from multiple
 *  processor cores.  The interface is quite simple, with two functions
 *  and a callback, which must be defined by the calling program.  The
 *  hand-off for finished rays is assigned to ray_fifo_out, which takes
 *  a single pointer to the finished ray and returns a non-negative
 *  integer.  If there is an exceptional condition where termination
 *  is desired, a negative value may be returned.
 *
 *  The ray_fifo_in() call takes a ray that has been initialized in
 *  the same manner as for the ray_pqueue() call, i.e., rayorigin()
 *  has been called and the origin, direction and maximum distance
 *  have all been assigned.  However, the ray number will be reset
 *  by ray_fifo_in() according to the number of rays traced since the
 *  last call to ray_fifo_flush().  This final call completes all
 *  pending ray calculations and frees the FIFO buffer.  If any of
 *  the automatic calls to the ray_fifo_out callback return a
 *  negative value, processing stops and -1 is returned.
 *
 *  Note:  The ray passed to ray_fifo_in() may be overwritten
 *  arbitrarily, since it is passed to ray_pqueue().
 */

#include  "ray.h"
#include  <string.h>

int             (*ray_fifo_out)(RAY *r) = NULL; /* ray output callback */

static RAY      *r_fifo_buf = NULL;             /* circular FIFO out buffer */
static int      r_fifo_len = 0;                 /* allocated FIFO length */
static RNUMBER  r_fifo_start = 1;               /* first awaited ray */
static RNUMBER  r_fifo_end = 1;                 /* one past FIFO last */
static RNUMBER  r_fifo_next = 1;                /* next ray assignment */

#define r_fifo(rn)      (&r_fifo_buf[(rn)&(r_fifo_len-1)])


static void
ray_fifo_growbuf(void)  /* double buffer size (or set to minimum if NULL) */
{
        RAY     *old_buf = r_fifo_buf;
        int     old_len = r_fifo_len;
        int     i;

        if (r_fifo_buf == NULL)
                r_fifo_len = 1<<5;
        else
                r_fifo_len <<= 1;
                                                /* allocate new */
        r_fifo_buf = (RAY *)calloc(r_fifo_len, sizeof(RAY));
        if (r_fifo_buf == NULL)
                error(SYSTEM, "out of memory in ray_fifo_growbuf");
        if (old_buf == NULL)
                return;
                                                /* copy old & free */
        for (i = r_fifo_start; i < r_fifo_end; i++)
                *r_fifo(i) = old_buf[i&(old_len-1)];

        free(old_buf);
}


static int
ray_fifo_push(          /* send finished ray to output (or queue it) */
        RAY *r
)
{
        int     rv, nsent = 0;

        if (ray_fifo_out == NULL)
                error(INTERNAL, "ray_fifo_out is NULL");
        if ((r->rno < r_fifo_start) | (r->rno >= r_fifo_next))
                error(INTERNAL, "unexpected ray number in ray_fifo_push()");

        if (r->rno > r_fifo_start) {            /* insert into output queue */
                while (r->rno - r_fifo_start >= r_fifo_len)
                        ray_fifo_growbuf();     /* need more space */
                *r_fifo(r->rno) = *r;
                if (r->rno >= r_fifo_end)
                        r_fifo_end = r->rno + 1;
                return(0);
        }
                        /* r->rno == r_fifo_start, so transfer ray(s) */
        do {
                rv = (*ray_fifo_out)(r);
                r->rno = 0;                     /* flag this entry complete */
                if (rv < 0)
                        return(-1);
                nsent += rv;
                if (++r_fifo_start < r_fifo_end)
                        r = r_fifo(r_fifo_start);
                else if (r_fifo_start > r_fifo_end)
                        r_fifo_end = r_fifo_start;
        } while (r->rno == r_fifo_start);

        return(nsent);
}


int
ray_fifo_in(            /* add ray to FIFO */
        RAY     *r
)
{
        static int      incall = 0;             /* prevent recursion */
        int             rv, rval = 0;

        if (incall++)
                error(INTERNAL, "recursive call to ray_fifo_in()");

        if (r_fifo_start >= 1L<<30) {           /* reset our counters */
                if ((rv = ray_fifo_flush()) < 0)
                        {--incall; return(-1);}
                rval += rv;
        }
                                                /* queue ray */
        r->rno = r_fifo_next++;
        if ((rv = ray_pqueue(r)) < 0)
                {--incall; return(-1);}

        if (!rv)                                /* no result this time? */
                {--incall; return(rval);}
        
        do {                                    /* else send/queue result */
                if ((rv = ray_fifo_push(r)) < 0)
                        {--incall; return(-1);}
                rval += rv;

        } while (ray_presult(r, -1) > 0);       /* empty in-core queue */

        --incall; return(rval);
}


int
ray_fifo_flush(void)    /* flush everything and release buffer */
{
        RAY     myRay;
        int     rv, rval = 0;
                                                /* clear parallel queue */
        while ((rv = ray_presult(&myRay, 0)) > 0 &&
                        (rv = ray_fifo_push(&myRay)) >= 0)
                rval += rv;

        if (rv < 0)                             /* check for exception */
                return(-1);

        if (r_fifo_start != r_fifo_end)
                error(INTERNAL, "could not empty queue in ray_fifo_flush()");

        if (r_fifo_buf != NULL) {
                free(r_fifo_buf);
                r_fifo_buf = NULL; r_fifo_len = 0;
        }
        r_fifo_next = r_fifo_end = r_fifo_start = 1;

        return(rval);
}
Revision:	2.4
Committed:	Sun Dec 13 19:13:04 2009 UTC (14 years, 4 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad4R2P2, rad5R0, rad5R1, rad4R2, rad4R1, rad4R0, rad4R2P1
Changes since 2.3:	+7 -7 lines
Log Message:	Eliminated restriction with -n and -I in rtrace
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.4	static const char RCSid[] = "$Id: rayfifo.c,v 2.3 2009/12/12 23:08:13 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* rayfifo.c - parallelize ray queue that respects order
6			*
7			* External symbols declared in ray.h
8			*/
9
10			#include "copyright.h"
11
12			/*
13			* These routines are essentially an adjunct to raypcalls.c, providing
14			* a convenient means to get first-in/first-out behavior from multiple
15			* processor cores. The interface is quite simple, with two functions
16			* and a callback, which must be defined by the calling program. The
17			* hand-off for finished rays is assigned to ray_fifo_out, which takes
18			* a single pointer to the finished ray and returns a non-negative
19			* integer. If there is an exceptional condition where termination
20			* is desired, a negative value may be returned.
21			*
22			* The ray_fifo_in() call takes a ray that has been initialized in
23	greg	2.4	* the same manner as for the ray_pqueue() call, i.e., rayorigin()
24			* has been called and the origin, direction and maximum distance
25			* have all been assigned. However, the ray number will be reset
26			* by ray_fifo_in() according to the number of rays traced since the
27	greg	2.1	* last call to ray_fifo_flush(). This final call completes all
28			* pending ray calculations and frees the FIFO buffer. If any of
29			* the automatic calls to the ray_fifo_out callback return a
30			* negative value, processing stops and -1 is returned.
31	greg	2.2	*
32			* Note: The ray passed to ray_fifo_in() may be overwritten
33			* arbitrarily, since it is passed to ray_pqueue().
34	greg	2.1	*/
35
36			#include "ray.h"
37			#include <string.h>
38
39			int (ray_fifo_out)(RAY r) = NULL; /* ray output callback */
40
41			static RAY r_fifo_buf = NULL; / circular FIFO out buffer */
42			static int r_fifo_len = 0; /* allocated FIFO length */
43			static RNUMBER r_fifo_start = 1; /* first awaited ray */
44			static RNUMBER r_fifo_end = 1; /* one past FIFO last */
45	greg	2.3	static RNUMBER r_fifo_next = 1; /* next ray assignment */
46	greg	2.1
47			#define r_fifo(rn) (&r_fifo_buf[(rn)&(r_fifo_len-1)])
48
49
50			static void
51			ray_fifo_growbuf(void) /* double buffer size (or set to minimum if NULL) */
52			{
53			RAY *old_buf = r_fifo_buf;
54			int old_len = r_fifo_len;
55			int i;
56
57			if (r_fifo_buf == NULL)
58	greg	2.4	r_fifo_len = 1<<5;
59	greg	2.1	else
60			r_fifo_len <<= 1;
61			/* allocate new */
62			r_fifo_buf = (RAY *)calloc(r_fifo_len, sizeof(RAY));
63			if (r_fifo_buf == NULL)
64			error(SYSTEM, "out of memory in ray_fifo_growbuf");
65			if (old_buf == NULL)
66			return;
67			/* copy old & free */
68			for (i = r_fifo_start; i < r_fifo_end; i++)
69			*r_fifo(i) = old_buf[i&(old_len-1)];
70
71			free(old_buf);
72			}
73
74
75			static int
76			ray_fifo_push( /* send finished ray to output (or queue it) */
77			RAY *r
78			)
79			{
80			int rv, nsent = 0;
81
82			if (ray_fifo_out == NULL)
83			error(INTERNAL, "ray_fifo_out is NULL");
84	greg	2.3	if ((r->rno < r_fifo_start) \| (r->rno >= r_fifo_next))
85			error(INTERNAL, "unexpected ray number in ray_fifo_push()");
86	greg	2.2
87	greg	2.1	if (r->rno > r_fifo_start) { /* insert into output queue */
88	greg	2.4	while (r->rno - r_fifo_start >= r_fifo_len)
89	greg	2.3	ray_fifo_growbuf(); /* need more space */
90	greg	2.1	r_fifo(r->rno) = r;
91	greg	2.3	if (r->rno >= r_fifo_end)
92			r_fifo_end = r->rno + 1;
93	greg	2.1	return(0);
94			}
95			/* r->rno == r_fifo_start, so transfer ray(s) */
96			do {
97	greg	2.3	rv = (*ray_fifo_out)(r);
98			r->rno = 0; /* flag this entry complete */
99			if (rv < 0)
100	greg	2.1	return(-1);
101			nsent += rv;
102			if (++r_fifo_start < r_fifo_end)
103			r = r_fifo(r_fifo_start);
104	greg	2.3	else if (r_fifo_start > r_fifo_end)
105			r_fifo_end = r_fifo_start;
106	greg	2.1	} while (r->rno == r_fifo_start);
107
108			return(nsent);
109			}
110
111
112			int
113			ray_fifo_in( /* add ray to FIFO */
114			RAY *r
115			)
116			{
117	greg	2.3	static int incall = 0; /* prevent recursion */
118			int rv, rval = 0;
119
120			if (incall++)
121			error(INTERNAL, "recursive call to ray_fifo_in()");
122	greg	2.1
123	greg	2.3	if (r_fifo_start >= 1L<<30) { /* reset our counters */
124	greg	2.1	if ((rv = ray_fifo_flush()) < 0)
125	greg	2.3	{--incall; return(-1);}
126	greg	2.1	rval += rv;
127			}
128			/* queue ray */
129	greg	2.3	r->rno = r_fifo_next++;
130	greg	2.1	if ((rv = ray_pqueue(r)) < 0)
131	greg	2.3	{--incall; return(-1);}
132	greg	2.1
133			if (!rv) /* no result this time? */
134	greg	2.3	{--incall; return(rval);}
135	greg	2.2
136			do { /* else send/queue result */
137			if ((rv = ray_fifo_push(r)) < 0)
138	greg	2.3	{--incall; return(-1);}
139	greg	2.2	rval += rv;
140
141			} while (ray_presult(r, -1) > 0); /* empty in-core queue */
142
143	greg	2.3	--incall; return(rval);
144	greg	2.1	}
145
146
147			int
148			ray_fifo_flush(void) /* flush everything and release buffer */
149			{
150			RAY myRay;
151			int rv, rval = 0;
152			/* clear parallel queue */
153			while ((rv = ray_presult(&myRay, 0)) > 0 &&
154			(rv = ray_fifo_push(&myRay)) >= 0)
155			rval += rv;
156
157	greg	2.3	if (rv < 0) /* check for exception */
158	greg	2.1	return(-1);
159
160			if (r_fifo_start != r_fifo_end)
161	greg	2.3	error(INTERNAL, "could not empty queue in ray_fifo_flush()");
162	greg	2.1
163	greg	2.3	if (r_fifo_buf != NULL) {
164			free(r_fifo_buf);
165			r_fifo_buf = NULL; r_fifo_len = 0;
166			}
167			r_fifo_next = r_fifo_end = r_fifo_start = 1;
168	greg	2.1
169			return(rval);
170			}