src/rt/raypcalls.c

#ifndef lint
static const char       RCSid[] = "$Id: raypcalls.c,v 2.17 2007/09/18 19:10:02 greg Exp $";
#endif
/*
 *  raypcalls.c - interface for parallel rendering using Radiance
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

/*
 *  These calls are designed similarly to the ones in raycalls.c,
 *  but allow for multiple rendering processes on the same host
 *  machine.  There is no sense in specifying more child processes
 *  than you have processors, but one child may help by allowing
 *  asynchronous ray computation in an interactive program, and
 *  will protect the caller from fatal rendering errors.
 *
 *  You should first read and undrstand the header in raycalls.c,
 *  as some things are explained there that are not repated here.
 *
 *  The first step is opening one or more rendering processes
 *  with a call to ray_pinit(oct, nproc).  Before calling fork(),
 *  ray_pinit() loads the octree and data structures into the
 *  caller's memory, and ray_popen() synchronizes the ambient
 *  file, if any.  Shared memory permits all sorts of queries
 *  that wouldn't be possible otherwise, without causing any real
 *  memory overhead, since all the static data are shared
 *  between processes.  Rays are then traced using a simple
 *  queuing mechanism, explained below.
 *
 *  The ray queue buffers RAYQLEN rays before sending to
 *  children, each of which may internally buffer RAYQLEN rays.
 *
 *  Rays are queued and returned by a single
 *  ray_pqueue() call.  A ray_pqueue() return
 *  value of 0 indicates that no rays are ready
 *  and the queue is not yet full.  A return value of 1
 *  indicates that a ray was returned, though it is probably
 *  not the one you just requested.  Rays may be identified by
 *  the rno member of the RAY struct, which is incremented
 *  by the rayorigin() call, or may be set explicitly by
 *  the caller.  Below is an example call sequence:
 *
 *      myRay.rorg = ( ray origin point )
 *      myRay.rdir = ( normalized ray direction )
 *      myRay.rmax = ( maximum length, or zero for no limit )
 *      rayorigin(&myRay, PRIMARY, NULL, NULL);
 *      myRay.rno = ( my personal ray identifier )
 *      if (ray_pqueue(&myRay) == 1)
 *              { do something with results }
 *
 *  Note the differences between this and the simpler ray_trace()
 *  call.  In particular, the call may or may not return a value
 *  in the passed ray structure.  Also, you need to call rayorigin()
 *  yourself, which is normally called for you by ray_trace().  The
 *  benefit is that ray_pqueue() will trace rays faster in
 *  proportion to the number of CPUs you have available on your
 *  system.  If the ray queue is full before the call, ray_pqueue()
 *  will block until a result is ready so it can queue this one.
 *  The global int ray_pnidle indicates the number of currently idle
 *  children.  If you want to check for completed rays without blocking,
 *  or get the results from rays that have been queued without
 *  queuing any new ones, the ray_presult() call is for you:
 *
 *      if (ray_presult(&myRay, 1) == 1)
 *              { do something with results }
 *
 *  If the second argument is 1, the call won't block when
 *  results aren't ready, but will immediately return 0.
 *  If the second argument is 0, the call will block
 *  until a value is available, returning 0 only if the
 *  queue is completely empty.  A negative return value
 *  indicates that a rendering process died.  If this
 *  happens, ray_close(0) is automatically called to close
 *  all child processes, and ray_pnprocs is set to zero.
 *
 *  If you just want to fill the ray queue without checking for
 *  results, check ray_pnidle and call ray_psend():
 *
 *      while (ray_pnidle) {
 *              ( set up ray )
 *              ray_psend(&myRay);
 *      }
 *
 *  Note that it is a fatal error to call ra_psend() when
 *  ray_pnidle is zero.  The ray_presult() and/or ray_pqueue()
 *  functions may be called subsequently to read back the results.
 *
 *  When you are done, you may call ray_pdone(1) to close
 *  all child processes and clean up memory used by Radiance.
 *  Any queued ray calculations will be awaited and discarded.
 *  As with ray_done(), ray_pdone(0) hangs onto data files
 *  and fonts that are likely to be used in subsequent renderings.
 *  Whether you want to bother cleaning up memory or not, you
 *  should at least call ray_pclose(0) to clean the child processes.
 *
 *  Warning:  You cannot affect any of the rendering processes
 *  by changing global parameter values onece ray_pinit() has
 *  been called.  Changing global parameters will have no effect
 *  until the next call to ray_pinit(), which restarts everything.
 *  If you just want to reap children so that you can alter the
 *  rendering parameters without reloading the scene, use the
 *  ray_pclose(0) and ray_popen(nproc) calls to close
 *  then restart the child processes after the changes are made.
 *
 *  Note:  These routines are written to coordinate with the
 *  definitions in raycalls.c, and in fact depend on them.
 *  If you want to trace a ray and get a result synchronously,
 *  use the ray_trace() call to compute it in the parent process.
 *  This will not interfere with any subprocess calculations,
 *  but beware that a fatal error may end with a call to quit().
 *
 *  Note:  One of the advantages of using separate processes
 *  is that it gives the calling program some immunity from
 *  fatal rendering errors.  As discussed in raycalls.c,
 *  Radiance tends to throw up its hands and exit at the
 *  first sign of trouble, calling quit() to return control
 *  to the top level.  Although you can avoid exit() with
 *  your own longjmp() in quit(), the cleanup afterwards
 *  is always suspect.  Through the use of subprocesses,
 *  we avoid this pitfall by closing the processes and
 *  returning a negative value from ray_pqueue() or
 *  ray_presult().  If you get a negative value from either
 *  of these calls, you can assume that the processes have
 *  been cleaned up with a call to ray_close(), though you
 *  will have to call ray_pdone() yourself if you want to
 *  free memory.  Obviously, you cannot continue rendering
 *  without risking further errors, but otherwise your
 *  process should not be compromised.
 */

#include  "rtprocess.h"
#include  "ray.h"
#include  "ambient.h"
#include  <sys/types.h>
#include  <sys/wait.h>
#include  "selcall.h"

#ifndef RAYQLEN
#define RAYQLEN         12              /* # rays to send at once */
#endif

#ifndef MAX_RPROCS
#if (FD_SETSIZE/2-4 < 64) 
#define MAX_NPROCS      (FD_SETSIZE/2-4)
#else
#define MAX_NPROCS      64              /* max. # rendering processes */
#endif
#endif

extern char     *shm_boundary;          /* boundary of shared memory */

int             ray_pnprocs = 0;        /* number of child processes */
int             ray_pnidle = 0;         /* number of idle children */

static struct child_proc {
        int     pid;                            /* child process id */
        int     fd_send;                        /* write to child here */
        int     fd_recv;                        /* read from child here */
        int     npending;                       /* # rays in process */
        unsigned long  rno[RAYQLEN];            /* working on these rays */
} r_proc[MAX_NPROCS];                   /* our child processes */

static RAY      r_queue[2*RAYQLEN];     /* ray i/o buffer */
static int      r_send_next;            /* next send ray placement */
static int      r_recv_first;           /* position of first unreported ray */
static int      r_recv_next;            /* next receive ray placement */

#define sendq_full()    (r_send_next >= RAYQLEN)

static int ray_pflush(void);
static void ray_pchild(int fd_in, int fd_out);


extern void
ray_pinit(              /* initialize ray-tracing processes */
        char    *otnm,
        int     nproc
)
{
        if (nobjects > 0)               /* close old calculation */
                ray_pdone(0);

        ray_init(otnm);                 /* load the shared scene */

        preload_objs();                 /* preload auxiliary data */

                                        /* set shared memory boundary */
        shm_boundary = (char *)malloc(16);
        strcpy(shm_boundary, "SHM_BOUNDARY");

        r_send_next = 0;                /* set up queue */
        r_recv_first = r_recv_next = RAYQLEN;

        ray_popen(nproc);               /* fork children */
}


static int
ray_pflush(void)                        /* send queued rays to idle children */
{
        int     nc, n, nw, i, sfirst;

        if ((ray_pnidle <= 0) | (r_send_next <= 0))
                return(0);              /* nothing we can send */
        
        sfirst = 0;                     /* divvy up labor */
        nc = ray_pnidle;
        for (i = ray_pnprocs; nc && i--; ) {
                if (r_proc[i].npending > 0)
                        continue;       /* child looks busy */
                n = (r_send_next - sfirst)/nc--;
                if (!n)
                        continue;
                                        /* smuggle set size in crtype */
                r_queue[sfirst].crtype = n;
                nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
                                sizeof(RAY)*n);
                if (nw != sizeof(RAY)*n)
                        return(-1);     /* write error */
                r_proc[i].npending = n;
                while (n--)             /* record ray IDs */
                        r_proc[i].rno[n] = r_queue[sfirst+n].rno;
                sfirst += r_proc[i].npending;
                ray_pnidle--;           /* now she's busy */
        }
        if (sfirst != r_send_next)
                error(CONSISTENCY, "code screwup in ray_pflush");
        r_send_next = 0;
        return(sfirst);                 /* return total # sent */
}


extern void
ray_psend(                      /* add a ray to our send queue */
        RAY     *r
)
{
        if (r == NULL)
                return;
                                        /* flush output if necessary */
        if (sendq_full() && ray_pflush() <= 0)
                error(INTERNAL, "ray_pflush failed in ray_psend");

        r_queue[r_send_next++] = *r;
}


extern int
ray_pqueue(                     /* queue a ray for computation */
        RAY     *r
)
{
        if (r == NULL)
                return(0);
                                        /* check for full send queue */
        if (sendq_full()) {
                RAY     mySend;
                int     rval;
                mySend = *r;
                                        /* wait for a result */
                rval = ray_presult(r, 0);
                                        /* put new ray in queue */
                r_queue[r_send_next++] = mySend;
                return(rval);           /* done */
        }
                                        /* else add ray to send queue */
        r_queue[r_send_next++] = *r;
                                        /* check for returned ray... */
        if (r_recv_first >= r_recv_next)
                return(0);
                                        /* ...one is sitting in queue */
        *r = r_queue[r_recv_first++];
        return(1);
}


extern int
ray_presult(            /* check for a completed ray */
        RAY     *r,
        int     poll
)
{
        static struct timeval   tpoll;  /* zero timeval struct */
        static fd_set   readset, errset;
        int     n, ok;
        register int    pn;

        if (r == NULL)
                return(0);
                                        /* check queued results first */
        if (r_recv_first < r_recv_next) {
                *r = r_queue[r_recv_first++];
                                        /* make sure send queue has room */
                if (sendq_full() && ray_pflush() <= 0)
                        return(-1);
                return(1);
        }
        n = ray_pnprocs - ray_pnidle;   /* pending before flush? */

        if (ray_pflush() < 0)           /* send new rays to process */
                return(-1);
                                        /* reset receive queue */
        r_recv_first = r_recv_next = RAYQLEN;

        if (!poll)                      /* count newly sent unless polling */
                n = ray_pnprocs - ray_pnidle;
        if (n <= 0)                     /* return if nothing to await */
                return(0);
        if (!poll && ray_pnprocs == 1)  /* one process -> skip select() */
                FD_SET(r_proc[0].fd_recv, &readset);

getready:                               /* any children waiting for us? */
        for (pn = ray_pnprocs; pn--; )
                if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
                                FD_ISSET(r_proc[pn].fd_recv, &errset))
                        break;
                                        /* call select if we must */
        if (pn < 0) {
                FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
                for (pn = ray_pnprocs; pn--; ) {
                        if (r_proc[pn].npending > 0)
                                FD_SET(r_proc[pn].fd_recv, &readset);
                        FD_SET(r_proc[pn].fd_recv, &errset);
                        if (r_proc[pn].fd_recv >= n)
                                n = r_proc[pn].fd_recv + 1;
                }
                                        /* find out who is ready */
                while ((n = select(n, &readset, (fd_set *)NULL, &errset,
                                poll ? &tpoll : (struct timeval *)NULL)) < 0)
                        if (errno != EINTR) {
                                error(WARNING,
                                        "select call failed in ray_presult");
                                ray_pclose(0);
                                return(-1);
                        }
                if (n > 0)              /* go back and get it */
                        goto getready;
                return(0);              /* else poll came up empty */
        }
        if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
                error(CONSISTENCY, "buffer shortage in ray_presult()");

                                        /* read rendered ray data */
        n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
                        sizeof(RAY)*r_proc[pn].npending);
        if (n > 0) {
                r_recv_next += n/sizeof(RAY);
                ok = (n == sizeof(RAY)*r_proc[pn].npending);
        } else
                ok = 0;
                                        /* reset child's status */
        FD_CLR(r_proc[pn].fd_recv, &readset);
        if (n <= 0)
                FD_CLR(r_proc[pn].fd_recv, &errset);
        r_proc[pn].npending = 0;
        ray_pnidle++;
                                        /* check for rendering errors */
        if (!ok) {
                ray_pclose(0);          /* process died -- clean up */
                return(-1);
        }
                                        /* preen returned rays */
        for (n = r_recv_next - r_recv_first; n--; ) {
                register RAY    *rp = &r_queue[r_recv_first + n];
                rp->rno = r_proc[pn].rno[n];
                rp->parent = NULL;
                rp->newcset = rp->clipset = NULL;
                rp->rox = NULL;
                rp->slights = NULL;
        }
                                        /* return first ray received */
        *r = r_queue[r_recv_first++];
        return(1);
}


extern void
ray_pdone(              /* reap children and free data */
        int     freall
)
{
        ray_pclose(0);                  /* close child processes */

        if (shm_boundary != NULL) {     /* clear shared memory boundary */
                free((void *)shm_boundary);
                shm_boundary = NULL;
        }
        ray_done(freall);               /* free rendering data */
}


static void
ray_pchild(     /* process rays (never returns) */
        int     fd_in,
        int     fd_out
)
{
        int     n;
        register int    i;
                                        /* flag child process for quit() */
        ray_pnprocs = -1;
                                        /* read each ray request set */
        while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
                int     n2;
                if (n < sizeof(RAY))
                        break;
                                        /* get smuggled set length */
                n2 = sizeof(RAY)*r_queue[0].crtype - n;
                if (n2 < 0)
                        error(INTERNAL, "buffer over-read in ray_pchild");
                if (n2 > 0) {           /* read the rest of the set */
                        i = readbuf(fd_in, (char *)r_queue + n, n2);
                        if (i != n2)
                                break;
                        n += n2;
                }
                n /= sizeof(RAY);
                                        /* evaluate rays */
                for (i = 0; i < n; i++) {
                        r_queue[i].crtype = r_queue[i].rtype;
                        r_queue[i].parent = NULL;
                        r_queue[i].clipset = NULL;
                        r_queue[i].slights = NULL;
                        samplendx++;
                        rayclear(&r_queue[i]);
                        rayvalue(&r_queue[i]);
                }
                                        /* write back our results */
                i = writebuf(fd_out, (char *)r_queue, sizeof(RAY)*n);
                if (i != sizeof(RAY)*n)
                        error(SYSTEM, "write error in ray_pchild");
        }
        if (n)
                error(SYSTEM, "read error in ray_pchild");
        ambsync();
        quit(0);                        /* normal exit */
}


extern void
ray_popen(                      /* open the specified # processes */
        int     nadd
)
{
                                        /* check if our table has room */
        if (ray_pnprocs + nadd > MAX_NPROCS)
                nadd = MAX_NPROCS - ray_pnprocs;
        if (nadd <= 0)
                return;
        ambsync();                      /* load any new ambient values */
        fflush(NULL);                   /* clear pending output */
        while (nadd--) {                /* fork each new process */
                int     p0[2], p1[2];
                if (pipe(p0) < 0 || pipe(p1) < 0)
                        error(SYSTEM, "cannot create pipe");
                if ((r_proc[ray_pnprocs].pid = fork()) == 0) {
                        int     pn;     /* close others' descriptors */
                        for (pn = ray_pnprocs; pn--; ) {
                                close(r_proc[pn].fd_send);
                                close(r_proc[pn].fd_recv);
                        }
                        close(p0[0]); close(p1[1]);
                                        /* following call never returns */
                        ray_pchild(p1[0], p0[1]);
                }
                if (r_proc[ray_pnprocs].pid < 0)
                        error(SYSTEM, "cannot fork child process");
                close(p1[0]); close(p0[1]);
                /*
                 * Close write stream on exec to avoid multiprocessing deadlock.
                 * No use in read stream without it, so set flag there as well.
                 */
                fcntl(p1[1], F_SETFD, FD_CLOEXEC);
                fcntl(p0[0], F_SETFD, FD_CLOEXEC);
                r_proc[ray_pnprocs].fd_send = p1[1];
                r_proc[ray_pnprocs].fd_recv = p0[0];
                r_proc[ray_pnprocs].npending = 0;
                ray_pnprocs++;
                ray_pnidle++;
        }
}


extern void
ray_pclose(             /* close one or more child processes */
        int     nsub
)
{
        static int      inclose = 0;
        RAY     res;
                                        /* check recursion */
        if (inclose)
                return;
        inclose++;
                                        /* check argument */
        if ((nsub <= 0) | (nsub > ray_pnprocs))
                nsub = ray_pnprocs;
                                        /* clear our ray queue */
        while (ray_presult(&res,0) > 0)
                ;
                                        /* clean up children */
        while (nsub--) {
                int     status;
                ray_pnprocs--;
                close(r_proc[ray_pnprocs].fd_recv);
                close(r_proc[ray_pnprocs].fd_send);
                if (waitpid(r_proc[ray_pnprocs].pid, &status, 0) < 0)
                        status = 127<<8;
                if (status) {
                        sprintf(errmsg,
                                "rendering process %d exited with code %d",
                                        r_proc[ray_pnprocs].pid, status>>8);
                        error(WARNING, errmsg);
                }
                ray_pnidle--;
        }
        inclose--;
}


void
quit(ec)                        /* make sure exit is called */
int     ec;
{
        if (ray_pnprocs > 0)    /* close children if any */
                ray_pclose(0);          
        exit(ec);
}
Revision:	2.18
Committed:	Fri Feb 8 18:27:31 2008 UTC (16 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.17:	+3 -5 lines
Log Message:	Created stub routines as placeholder for Windows version of raypcalls
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.18	static const char RCSid[] = "$Id: raypcalls.c,v 2.17 2007/09/18 19:10:02 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* raypcalls.c - interface for parallel rendering using Radiance
6			*
7			* External symbols declared in ray.h
8			*/
9
10	greg	2.2	#include "copyright.h"
11	greg	2.1
12			/*
13			* These calls are designed similarly to the ones in raycalls.c,
14			* but allow for multiple rendering processes on the same host
15			* machine. There is no sense in specifying more child processes
16			* than you have processors, but one child may help by allowing
17			* asynchronous ray computation in an interactive program, and
18			* will protect the caller from fatal rendering errors.
19			*
20			* You should first read and undrstand the header in raycalls.c,
21			* as some things are explained there that are not repated here.
22			*
23			* The first step is opening one or more rendering processes
24			* with a call to ray_pinit(oct, nproc). Before calling fork(),
25			* ray_pinit() loads the octree and data structures into the
26	greg	2.13	* caller's memory, and ray_popen() synchronizes the ambient
27			* file, if any. Shared memory permits all sorts of queries
28			* that wouldn't be possible otherwise, without causing any real
29	greg	2.1	* memory overhead, since all the static data are shared
30			* between processes. Rays are then traced using a simple
31			* queuing mechanism, explained below.
32			*
33	greg	2.14	* The ray queue buffers RAYQLEN rays before sending to
34			* children, each of which may internally buffer RAYQLEN rays.
35			*
36	greg	2.13	* Rays are queued and returned by a single
37	greg	2.1	* ray_pqueue() call. A ray_pqueue() return
38			* value of 0 indicates that no rays are ready
39			* and the queue is not yet full. A return value of 1
40			* indicates that a ray was returned, though it is probably
41			* not the one you just requested. Rays may be identified by
42			* the rno member of the RAY struct, which is incremented
43			* by the rayorigin() call, or may be set explicitly by
44			* the caller. Below is an example call sequence:
45			*
46			* myRay.rorg = ( ray origin point )
47			* myRay.rdir = ( normalized ray direction )
48			* myRay.rmax = ( maximum length, or zero for no limit )
49	greg	2.11	* rayorigin(&myRay, PRIMARY, NULL, NULL);
50	greg	2.1	* myRay.rno = ( my personal ray identifier )
51			* if (ray_pqueue(&myRay) == 1)
52			* { do something with results }
53			*
54			* Note the differences between this and the simpler ray_trace()
55			* call. In particular, the call may or may not return a value
56			* in the passed ray structure. Also, you need to call rayorigin()
57	greg	2.7	* yourself, which is normally called for you by ray_trace(). The
58			* benefit is that ray_pqueue() will trace rays faster in
59	greg	2.1	* proportion to the number of CPUs you have available on your
60			* system. If the ray queue is full before the call, ray_pqueue()
61			* will block until a result is ready so it can queue this one.
62	greg	2.3	* The global int ray_pnidle indicates the number of currently idle
63	greg	2.1	* children. If you want to check for completed rays without blocking,
64			* or get the results from rays that have been queued without
65			* queuing any new ones, the ray_presult() call is for you:
66			*
67			* if (ray_presult(&myRay, 1) == 1)
68			* { do something with results }
69			*
70			* If the second argument is 1, the call won't block when
71			* results aren't ready, but will immediately return 0.
72			* If the second argument is 0, the call will block
73			* until a value is available, returning 0 only if the
74			* queue is completely empty. A negative return value
75			* indicates that a rendering process died. If this
76			* happens, ray_close(0) is automatically called to close
77	greg	2.3	* all child processes, and ray_pnprocs is set to zero.
78	greg	2.1	*
79			* If you just want to fill the ray queue without checking for
80	greg	2.3	* results, check ray_pnidle and call ray_psend():
81	greg	2.1	*
82	greg	2.3	* while (ray_pnidle) {
83	greg	2.1	* ( set up ray )
84			* ray_psend(&myRay);
85			* }
86			*
87	greg	2.7	* Note that it is a fatal error to call ra_psend() when
88			* ray_pnidle is zero. The ray_presult() and/or ray_pqueue()
89			* functions may be called subsequently to read back the results.
90	greg	2.1	*
91			* When you are done, you may call ray_pdone(1) to close
92			* all child processes and clean up memory used by Radiance.
93			* Any queued ray calculations will be awaited and discarded.
94			* As with ray_done(), ray_pdone(0) hangs onto data files
95			* and fonts that are likely to be used in subsequent renderings.
96			* Whether you want to bother cleaning up memory or not, you
97			* should at least call ray_pclose(0) to clean the child processes.
98			*
99			* Warning: You cannot affect any of the rendering processes
100			* by changing global parameter values onece ray_pinit() has
101			* been called. Changing global parameters will have no effect
102			* until the next call to ray_pinit(), which restarts everything.
103			* If you just want to reap children so that you can alter the
104			* rendering parameters without reloading the scene, use the
105			* ray_pclose(0) and ray_popen(nproc) calls to close
106	greg	2.7	* then restart the child processes after the changes are made.
107	greg	2.1	*
108			* Note: These routines are written to coordinate with the
109			* definitions in raycalls.c, and in fact depend on them.
110			* If you want to trace a ray and get a result synchronously,
111	greg	2.13	* use the ray_trace() call to compute it in the parent process.
112	greg	2.7	* This will not interfere with any subprocess calculations,
113			* but beware that a fatal error may end with a call to quit().
114	greg	2.1	*
115			* Note: One of the advantages of using separate processes
116			* is that it gives the calling program some immunity from
117			* fatal rendering errors. As discussed in raycalls.c,
118			* Radiance tends to throw up its hands and exit at the
119			* first sign of trouble, calling quit() to return control
120	greg	2.7	* to the top level. Although you can avoid exit() with
121	greg	2.1	* your own longjmp() in quit(), the cleanup afterwards
122			* is always suspect. Through the use of subprocesses,
123			* we avoid this pitfall by closing the processes and
124			* returning a negative value from ray_pqueue() or
125			* ray_presult(). If you get a negative value from either
126			* of these calls, you can assume that the processes have
127			* been cleaned up with a call to ray_close(), though you
128			* will have to call ray_pdone() yourself if you want to
129	greg	2.7	* free memory. Obviously, you cannot continue rendering
130			* without risking further errors, but otherwise your
131			* process should not be compromised.
132	greg	2.1	*/
133
134	schorsch	2.6	#include "rtprocess.h"
135	greg	2.1	#include "ray.h"
136	schorsch	2.6	#include "ambient.h"
137	greg	2.18	#include <sys/types.h>
138			#include <sys/wait.h>
139	greg	2.1	#include "selcall.h"
140
141			#ifndef RAYQLEN
142	greg	2.13	#define RAYQLEN 12 /* # rays to send at once */
143	greg	2.1	#endif
144
145			#ifndef MAX_RPROCS
146			#if (FD_SETSIZE/2-4 < 64)
147			#define MAX_NPROCS (FD_SETSIZE/2-4)
148			#else
149			#define MAX_NPROCS 64 /* max. # rendering processes */
150			#endif
151			#endif
152
153			extern char shm_boundary; / boundary of shared memory */
154
155	greg	2.3	int ray_pnprocs = 0; /* number of child processes */
156			int ray_pnidle = 0; /* number of idle children */
157	greg	2.1
158			static struct child_proc {
159			int pid; /* child process id */
160			int fd_send; /* write to child here */
161			int fd_recv; /* read from child here */
162			int npending; /* # rays in process */
163			unsigned long rno[RAYQLEN]; /* working on these rays */
164			} r_proc[MAX_NPROCS]; /* our child processes */
165
166			static RAY r_queue[2RAYQLEN]; / ray i/o buffer */
167			static int r_send_next; /* next send ray placement */
168			static int r_recv_first; /* position of first unreported ray */
169			static int r_recv_next; /* next receive ray placement */
170
171			#define sendq_full() (r_send_next >= RAYQLEN)
172
173	schorsch	2.6	static int ray_pflush(void);
174	greg	2.13	static void ray_pchild(int fd_in, int fd_out);
175	greg	2.1
176	schorsch	2.6
177			extern void
178			ray_pinit( /* initialize ray-tracing processes */
179			char *otnm,
180			int nproc
181			)
182	greg	2.1	{
183			if (nobjects > 0) /* close old calculation */
184			ray_pdone(0);
185
186			ray_init(otnm); /* load the shared scene */
187
188			preload_objs(); /* preload auxiliary data */
189
190			/* set shared memory boundary */
191			shm_boundary = (char *)malloc(16);
192			strcpy(shm_boundary, "SHM_BOUNDARY");
193
194			r_send_next = 0; /* set up queue */
195			r_recv_first = r_recv_next = RAYQLEN;
196
197			ray_popen(nproc); /* fork children */
198			}
199
200
201			static int
202	schorsch	2.6	ray_pflush(void) /* send queued rays to idle children */
203	greg	2.1	{
204			int nc, n, nw, i, sfirst;
205
206	schorsch	2.5	if ((ray_pnidle <= 0) \| (r_send_next <= 0))
207	greg	2.1	return(0); /* nothing we can send */
208
209			sfirst = 0; /* divvy up labor */
210	greg	2.3	nc = ray_pnidle;
211			for (i = ray_pnprocs; nc && i--; ) {
212	greg	2.1	if (r_proc[i].npending > 0)
213			continue; /* child looks busy */
214			n = (r_send_next - sfirst)/nc--;
215			if (!n)
216			continue;
217			/* smuggle set size in crtype */
218			r_queue[sfirst].crtype = n;
219			nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
220			sizeof(RAY)*n);
221			if (nw != sizeof(RAY)*n)
222			return(-1); /* write error */
223			r_proc[i].npending = n;
224			while (n--) /* record ray IDs */
225			r_proc[i].rno[n] = r_queue[sfirst+n].rno;
226			sfirst += r_proc[i].npending;
227	greg	2.3	ray_pnidle--; /* now she's busy */
228	greg	2.1	}
229			if (sfirst != r_send_next)
230			error(CONSISTENCY, "code screwup in ray_pflush");
231			r_send_next = 0;
232			return(sfirst); /* return total # sent */
233			}
234
235
236	schorsch	2.6	extern void
237			ray_psend( /* add a ray to our send queue */
238			RAY *r
239			)
240	greg	2.1	{
241			if (r == NULL)
242			return;
243			/* flush output if necessary */
244			if (sendq_full() && ray_pflush() <= 0)
245			error(INTERNAL, "ray_pflush failed in ray_psend");
246
247	greg	2.14	r_queue[r_send_next++] = *r;
248	greg	2.1	}
249
250
251	schorsch	2.6	extern int
252			ray_pqueue( /* queue a ray for computation */
253			RAY *r
254			)
255	greg	2.1	{
256			if (r == NULL)
257			return(0);
258			/* check for full send queue */
259			if (sendq_full()) {
260			RAY mySend;
261			int rval;
262	schorsch	2.4	mySend = *r;
263	greg	2.1	/* wait for a result */
264			rval = ray_presult(r, 0);
265			/* put new ray in queue */
266	greg	2.14	r_queue[r_send_next++] = mySend;
267	greg	2.1	return(rval); /* done */
268			}
269	greg	2.13	/* else add ray to send queue */
270	greg	2.14	r_queue[r_send_next++] = *r;
271	greg	2.1	/* check for returned ray... */
272			if (r_recv_first >= r_recv_next)
273			return(0);
274			/* ...one is sitting in queue */
275	greg	2.14	*r = r_queue[r_recv_first++];
276	greg	2.1	return(1);
277			}
278
279
280	schorsch	2.6	extern int
281			ray_presult( /* check for a completed ray */
282			RAY *r,
283			int poll
284			)
285	greg	2.1	{
286			static struct timeval tpoll; /* zero timeval struct */
287			static fd_set readset, errset;
288			int n, ok;
289			register int pn;
290
291			if (r == NULL)
292			return(0);
293			/* check queued results first */
294			if (r_recv_first < r_recv_next) {
295	greg	2.14	*r = r_queue[r_recv_first++];
296	greg	2.17	/* make sure send queue has room */
297			if (sendq_full() && ray_pflush() <= 0)
298			return(-1);
299	greg	2.1	return(1);
300			}
301	greg	2.3	n = ray_pnprocs - ray_pnidle; /* pending before flush? */
302	greg	2.1
303			if (ray_pflush() < 0) /* send new rays to process */
304			return(-1);
305			/* reset receive queue */
306			r_recv_first = r_recv_next = RAYQLEN;
307
308			if (!poll) /* count newly sent unless polling */
309	greg	2.3	n = ray_pnprocs - ray_pnidle;
310	greg	2.1	if (n <= 0) /* return if nothing to await */
311			return(0);
312	greg	2.16	if (!poll && ray_pnprocs == 1) /* one process -> skip select() */
313			FD_SET(r_proc[0].fd_recv, &readset);
314
315	greg	2.1	getready: /* any children waiting for us? */
316	greg	2.3	for (pn = ray_pnprocs; pn--; )
317	greg	2.1	if (FD_ISSET(r_proc[pn].fd_recv, &readset) \|\|
318			FD_ISSET(r_proc[pn].fd_recv, &errset))
319			break;
320			/* call select if we must */
321			if (pn < 0) {
322			FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
323	greg	2.3	for (pn = ray_pnprocs; pn--; ) {
324	greg	2.1	if (r_proc[pn].npending > 0)
325			FD_SET(r_proc[pn].fd_recv, &readset);
326			FD_SET(r_proc[pn].fd_recv, &errset);
327			if (r_proc[pn].fd_recv >= n)
328			n = r_proc[pn].fd_recv + 1;
329			}
330			/* find out who is ready */
331			while ((n = select(n, &readset, (fd_set *)NULL, &errset,
332			poll ? &tpoll : (struct timeval *)NULL)) < 0)
333			if (errno != EINTR) {
334			error(WARNING,
335			"select call failed in ray_presult");
336			ray_pclose(0);
337			return(-1);
338			}
339			if (n > 0) /* go back and get it */
340			goto getready;
341			return(0); /* else poll came up empty */
342			}
343			if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
344			error(CONSISTENCY, "buffer shortage in ray_presult()");
345
346			/* read rendered ray data */
347			n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
348			sizeof(RAY)*r_proc[pn].npending);
349			if (n > 0) {
350			r_recv_next += n/sizeof(RAY);
351			ok = (n == sizeof(RAY)*r_proc[pn].npending);
352			} else
353			ok = 0;
354			/* reset child's status */
355			FD_CLR(r_proc[pn].fd_recv, &readset);
356			if (n <= 0)
357			FD_CLR(r_proc[pn].fd_recv, &errset);
358			r_proc[pn].npending = 0;
359	greg	2.3	ray_pnidle++;
360	greg	2.1	/* check for rendering errors */
361			if (!ok) {
362			ray_pclose(0); /* process died -- clean up */
363			return(-1);
364			}
365			/* preen returned rays */
366			for (n = r_recv_next - r_recv_first; n--; ) {
367			register RAY *rp = &r_queue[r_recv_first + n];
368			rp->rno = r_proc[pn].rno[n];
369			rp->parent = NULL;
370			rp->newcset = rp->clipset = NULL;
371			rp->rox = NULL;
372			rp->slights = NULL;
373			}
374			/* return first ray received */
375	greg	2.13	*r = r_queue[r_recv_first++];
376	greg	2.1	return(1);
377			}
378
379
380	schorsch	2.6	extern void
381			ray_pdone( /* reap children and free data */
382			int freall
383			)
384	greg	2.1	{
385			ray_pclose(0); /* close child processes */
386
387			if (shm_boundary != NULL) { /* clear shared memory boundary */
388			free((void *)shm_boundary);
389			shm_boundary = NULL;
390			}
391			ray_done(freall); /* free rendering data */
392			}
393
394
395			static void
396	schorsch	2.6	ray_pchild( /* process rays (never returns) */
397			int fd_in,
398			int fd_out
399			)
400	greg	2.1	{
401			int n;
402			register int i;
403	greg	2.15	/* flag child process for quit() */
404			ray_pnprocs = -1;
405	greg	2.1	/* read each ray request set */
406			while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
407			int n2;
408	greg	2.12	if (n < sizeof(RAY))
409	greg	2.1	break;
410			/* get smuggled set length */
411	greg	2.12	n2 = sizeof(RAY)*r_queue[0].crtype - n;
412	greg	2.1	if (n2 < 0)
413			error(INTERNAL, "buffer over-read in ray_pchild");
414			if (n2 > 0) { /* read the rest of the set */
415	greg	2.12	i = readbuf(fd_in, (char *)r_queue + n, n2);
416			if (i != n2)
417	greg	2.1	break;
418			n += n2;
419			}
420	greg	2.12	n /= sizeof(RAY);
421	greg	2.1	/* evaluate rays */
422			for (i = 0; i < n; i++) {
423			r_queue[i].crtype = r_queue[i].rtype;
424			r_queue[i].parent = NULL;
425			r_queue[i].clipset = NULL;
426			r_queue[i].slights = NULL;
427			samplendx++;
428			rayclear(&r_queue[i]);
429			rayvalue(&r_queue[i]);
430			}
431			/* write back our results */
432			i = writebuf(fd_out, (char )r_queue, sizeof(RAY)n);
433			if (i != sizeof(RAY)*n)
434			error(SYSTEM, "write error in ray_pchild");
435			}
436			if (n)
437			error(SYSTEM, "read error in ray_pchild");
438			ambsync();
439			quit(0); /* normal exit */
440			}
441
442
443	schorsch	2.6	extern void
444			ray_popen( /* open the specified # processes */
445			int nadd
446			)
447	greg	2.1	{
448			/* check if our table has room */
449	greg	2.3	if (ray_pnprocs + nadd > MAX_NPROCS)
450			nadd = MAX_NPROCS - ray_pnprocs;
451	greg	2.1	if (nadd <= 0)
452			return;
453	greg	2.13	ambsync(); /* load any new ambient values */
454			fflush(NULL); /* clear pending output */
455	greg	2.1	while (nadd--) { /* fork each new process */
456			int p0[2], p1[2];
457			if (pipe(p0) < 0 \|\| pipe(p1) < 0)
458			error(SYSTEM, "cannot create pipe");
459	greg	2.3	if ((r_proc[ray_pnprocs].pid = fork()) == 0) {
460	greg	2.1	int pn; /* close others' descriptors */
461	greg	2.3	for (pn = ray_pnprocs; pn--; ) {
462	greg	2.1	close(r_proc[pn].fd_send);
463			close(r_proc[pn].fd_recv);
464			}
465			close(p0[0]); close(p1[1]);
466			/* following call never returns */
467			ray_pchild(p1[0], p0[1]);
468			}
469	greg	2.3	if (r_proc[ray_pnprocs].pid < 0)
470	greg	2.1	error(SYSTEM, "cannot fork child process");
471			close(p1[0]); close(p0[1]);
472	greg	2.9	/*
473			* Close write stream on exec to avoid multiprocessing deadlock.
474			* No use in read stream without it, so set flag there as well.
475			*/
476			fcntl(p1[1], F_SETFD, FD_CLOEXEC);
477			fcntl(p0[0], F_SETFD, FD_CLOEXEC);
478	greg	2.3	r_proc[ray_pnprocs].fd_send = p1[1];
479			r_proc[ray_pnprocs].fd_recv = p0[0];
480			r_proc[ray_pnprocs].npending = 0;
481			ray_pnprocs++;
482			ray_pnidle++;
483	greg	2.1	}
484			}
485
486
487	schorsch	2.6	extern void
488			ray_pclose( /* close one or more child processes */
489			int nsub
490			)
491	greg	2.1	{
492			static int inclose = 0;
493			RAY res;
494			/* check recursion */
495			if (inclose)
496			return;
497			inclose++;
498			/* check argument */
499	schorsch	2.5	if ((nsub <= 0) \| (nsub > ray_pnprocs))
500	greg	2.3	nsub = ray_pnprocs;
501	greg	2.1	/* clear our ray queue */
502			while (ray_presult(&res,0) > 0)
503			;
504			/* clean up children */
505			while (nsub--) {
506			int status;
507	greg	2.3	ray_pnprocs--;
508			close(r_proc[ray_pnprocs].fd_recv);
509			close(r_proc[ray_pnprocs].fd_send);
510	greg	2.8	if (waitpid(r_proc[ray_pnprocs].pid, &status, 0) < 0)
511			status = 127<<8;
512	greg	2.1	if (status) {
513			sprintf(errmsg,
514			"rendering process %d exited with code %d",
515	greg	2.3	r_proc[ray_pnprocs].pid, status>>8);
516	greg	2.1	error(WARNING, errmsg);
517			}
518	greg	2.3	ray_pnidle--;
519	greg	2.1	}
520			inclose--;
521			}
522
523
524			void
525			quit(ec) /* make sure exit is called */
526			int ec;
527			{
528	greg	2.15	if (ray_pnprocs > 0) /* close children if any */
529			ray_pclose(0);
530	greg	2.1	exit(ec);
531			}