src/rt/rayfifo.c

#ifndef lint
static const char RCSid[] = "$Id: rayfifo.c,v 2.1 2009/12/12 05:20:10 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_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.
 *
 *  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 */

#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 >= r_fifo_len)
                ray_fifo_growbuf();             /* need more space */

        if (r->rno > r_fifo_start) {            /* insert into output queue */
                *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);
        
        do {                                    /* else send/queue result */
                if ((rv = ray_fifo_push(r)) < 0)
                        return(-1);
                rval += rv;

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

        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:	2.2
Committed:	Sat Dec 12 19:01:00 2009 UTC (14 years, 4 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.1:	+15 -7 lines
Log Message:	Added -n option to rtrace and moved quit() funciton out of raypcalls
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.2	static const char RCSid[] = "$Id: rayfifo.c,v 2.1 2009/12/12 05:20:10 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			* 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	greg	2.2	*
31			* Note: The ray passed to ray_fifo_in() may be overwritten
32			* arbitrarily, since it is passed to ray_pqueue().
33	greg	2.1	*/
34
35			#include "ray.h"
36			#include <string.h>
37
38			int (ray_fifo_out)(RAY r) = NULL; /* ray output callback */
39
40			static RAY r_fifo_buf = NULL; / circular FIFO out buffer */
41			static int r_fifo_len = 0; /* allocated FIFO length */
42			static RNUMBER r_fifo_start = 1; /* first awaited ray */
43			static RNUMBER r_fifo_end = 1; /* one past FIFO last */
44
45			#define r_fifo(rn) (&r_fifo_buf[(rn)&(r_fifo_len-1)])
46
47
48			static void
49			ray_fifo_growbuf(void) /* double buffer size (or set to minimum if NULL) */
50			{
51			RAY *old_buf = r_fifo_buf;
52			int old_len = r_fifo_len;
53			int i;
54
55			if (r_fifo_buf == NULL)
56			r_fifo_len = 1<<4;
57			else
58			r_fifo_len <<= 1;
59			/* allocate new */
60			r_fifo_buf = (RAY *)calloc(r_fifo_len, sizeof(RAY));
61			if (r_fifo_buf == NULL)
62			error(SYSTEM, "out of memory in ray_fifo_growbuf");
63			if (old_buf == NULL)
64			return;
65			/* copy old & free */
66			for (i = r_fifo_start; i < r_fifo_end; i++)
67			*r_fifo(i) = old_buf[i&(old_len-1)];
68
69			free(old_buf);
70			}
71
72
73			static int
74			ray_fifo_push( /* send finished ray to output (or queue it) */
75			RAY *r
76			)
77			{
78			int rv, nsent = 0;
79
80			if (ray_fifo_out == NULL)
81			error(INTERNAL, "ray_fifo_out is NULL");
82			if ((r->rno < r_fifo_start) \| (r->rno >= r_fifo_end))
83			error(INTERNAL, "unexpected ray number in ray_fifo_push");
84
85	greg	2.2	if (r->rno - r_fifo_start >= r_fifo_len)
86			ray_fifo_growbuf(); /* need more space */
87
88	greg	2.1	if (r->rno > r_fifo_start) { /* insert into output queue */
89			r_fifo(r->rno) = r;
90			return(0);
91			}
92			/* r->rno == r_fifo_start, so transfer ray(s) */
93			do {
94			if ((rv = (*ray_fifo_out)(r)) < 0)
95			return(-1);
96			nsent += rv;
97			if (++r_fifo_start < r_fifo_end)
98			r = r_fifo(r_fifo_start);
99			} while (r->rno == r_fifo_start);
100
101			return(nsent);
102			}
103
104
105			int
106			ray_fifo_in( /* add ray to FIFO */
107			RAY *r
108			)
109			{
110			int rv, rval = 0;
111
112			if (r_fifo_start >= 1L<<30) { /* reset our counter */
113			if ((rv = ray_fifo_flush()) < 0)
114			return(-1);
115			rval += rv;
116			}
117			/* queue ray */
118			rayorigin(r, PRIMARY, NULL, NULL);
119			r->rno = r_fifo_end++;
120			if ((rv = ray_pqueue(r)) < 0)
121			return(-1);
122
123			if (!rv) /* no result this time? */
124			return(rval);
125	greg	2.2
126			do { /* else send/queue result */
127			if ((rv = ray_fifo_push(r)) < 0)
128			return(-1);
129			rval += rv;
130
131			} while (ray_presult(r, -1) > 0); /* empty in-core queue */
132
133	greg	2.1	return(rval);
134			}
135
136
137			int
138			ray_fifo_flush(void) /* flush everything and release buffer */
139			{
140			RAY myRay;
141			int rv, rval = 0;
142			/* clear parallel queue */
143			while ((rv = ray_presult(&myRay, 0)) > 0 &&
144			(rv = ray_fifo_push(&myRay)) >= 0)
145			rval += rv;
146
147			if (rv < 0) /* check for error */
148			return(-1);
149
150			if (r_fifo_start != r_fifo_end)
151			error(INTERNAL, "could not empty queue in ray_fifo_flush");
152
153			free(r_fifo_buf);
154			r_fifo_buf = NULL;
155			r_fifo_len = 0;
156			r_fifo_end = r_fifo_start = 1;
157
158			return(rval);
159			}