src/rt/rayfifo.c

#ifndef lint
static const char RCSid[] = "$Id$";
#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_trace() call, i.e., the origin,
 *  direction, and maximum length have been assigned. The ray number
 *  will be set 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.
 */

#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 */

#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<<4;
        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_end))
                error(INTERNAL, "unexpected ray number in ray_fifo_push");

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

        return(nsent);
}


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

        if (r_fifo_start >= 1L<<30) {           /* reset our counter */
                if ((rv = ray_fifo_flush()) < 0)
                        return(-1);
                rval += rv;
        }
                                                /* queue ray */
        rayorigin(r, PRIMARY, NULL, NULL);
        r->rno = r_fifo_end++;
        if ((rv = ray_pqueue(r)) < 0)
                return(-1);

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

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

        free(r_fifo_buf);
        r_fifo_buf = NULL;
        r_fifo_len = 0;
        r_fifo_end = r_fifo_start = 1;

        return(rval);
}
Revision:	2.1
Committed:	Sat Dec 12 05:20:10 2009 UTC (14 years, 4 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Log Message:	Created FIFO calls for ray multiprocessing
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2			static const char RCSid[] = "$Id$";
3			#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			* the same manner as for the ray_trace() call, i.e., the origin,
24			* direction, and maximum length have been assigned. The ray number
25			* will be set according to the number of rays traced since the
26			* last call to ray_fifo_flush(). This final call completes all
27			* pending ray calculations and frees the FIFO buffer. If any of
28			* the automatic calls to the ray_fifo_out callback return a
29			* negative value, processing stops and -1 is returned.
30			*/
31
32			#include "ray.h"
33			#include <string.h>
34
35			int (ray_fifo_out)(RAY r) = NULL; /* ray output callback */
36
37			static RAY r_fifo_buf = NULL; / circular FIFO out buffer */
38			static int r_fifo_len = 0; /* allocated FIFO length */
39			static RNUMBER r_fifo_start = 1; /* first awaited ray */
40			static RNUMBER r_fifo_end = 1; /* one past FIFO last */
41
42			#define r_fifo(rn) (&r_fifo_buf[(rn)&(r_fifo_len-1)])
43
44
45			static void
46			ray_fifo_growbuf(void) /* double buffer size (or set to minimum if NULL) */
47			{
48			RAY *old_buf = r_fifo_buf;
49			int old_len = r_fifo_len;
50			int i;
51
52			if (r_fifo_buf == NULL)
53			r_fifo_len = 1<<4;
54			else
55			r_fifo_len <<= 1;
56			/* allocate new */
57			r_fifo_buf = (RAY *)calloc(r_fifo_len, sizeof(RAY));
58			if (r_fifo_buf == NULL)
59			error(SYSTEM, "out of memory in ray_fifo_growbuf");
60			if (old_buf == NULL)
61			return;
62			/* copy old & free */
63			for (i = r_fifo_start; i < r_fifo_end; i++)
64			*r_fifo(i) = old_buf[i&(old_len-1)];
65
66			free(old_buf);
67			}
68
69
70			static int
71			ray_fifo_push( /* send finished ray to output (or queue it) */
72			RAY *r
73			)
74			{
75			int rv, nsent = 0;
76
77			if (ray_fifo_out == NULL)
78			error(INTERNAL, "ray_fifo_out is NULL");
79			if ((r->rno < r_fifo_start) \| (r->rno >= r_fifo_end))
80			error(INTERNAL, "unexpected ray number in ray_fifo_push");
81
82			if (r->rno > r_fifo_start) { /* insert into output queue */
83			if (r->rno - r_fifo_start >= r_fifo_len)
84			ray_fifo_growbuf();
85			r_fifo(r->rno) = r;
86			return(0);
87			}
88			/* r->rno == r_fifo_start, so transfer ray(s) */
89			do {
90			if ((rv = (*ray_fifo_out)(r)) < 0)
91			return(-1);
92			nsent += rv;
93			if (++r_fifo_start < r_fifo_end)
94			r = r_fifo(r_fifo_start);
95			} while (r->rno == r_fifo_start);
96
97			return(nsent);
98			}
99
100
101			int
102			ray_fifo_in( /* add ray to FIFO */
103			RAY *r
104			)
105			{
106			int rv, rval = 0;
107
108			if (r_fifo_start >= 1L<<30) { /* reset our counter */
109			if ((rv = ray_fifo_flush()) < 0)
110			return(-1);
111			rval += rv;
112			}
113			/* queue ray */
114			rayorigin(r, PRIMARY, NULL, NULL);
115			r->rno = r_fifo_end++;
116			if ((rv = ray_pqueue(r)) < 0)
117			return(-1);
118
119			if (!rv) /* no result this time? */
120			return(rval);
121			/* else send/queue result */
122			if ((rv = ray_fifo_push(r)) < 0)
123			return(-1);
124			rval += rv;
125			return(rval);
126			}
127
128
129			int
130			ray_fifo_flush(void) /* flush everything and release buffer */
131			{
132			RAY myRay;
133			int rv, rval = 0;
134			/* clear parallel queue */
135			while ((rv = ray_presult(&myRay, 0)) > 0 &&
136			(rv = ray_fifo_push(&myRay)) >= 0)
137			rval += rv;
138
139			if (rv < 0) /* check for error */
140			return(-1);
141
142			if (r_fifo_start != r_fifo_end)
143			error(INTERNAL, "could not empty queue in ray_fifo_flush");
144
145			free(r_fifo_buf);
146			r_fifo_buf = NULL;
147			r_fifo_len = 0;
148			r_fifo_end = r_fifo_start = 1;
149
150			return(rval);
151			}