--- ray/src/rt/raypcalls.c	2009/12/15 18:21:53	2.25
+++ ray/src/rt/raypcalls.c	2020/06/16 17:58:11	2.34
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: raypcalls.c,v 2.25 2009/12/15 18:21:53 greg Exp $";
+static const char	RCSid[] = "$Id: raypcalls.c,v 2.34 2020/06/16 17:58:11 greg Exp $";
 #endif
 /*
  *  raypcalls.c - interface for parallel rendering using Radiance
@@ -71,11 +71,11 @@ static const char	RCSid[] = "$Id: raypcalls.c,v 2.25 2
  *
  *  If the second argument is 1, the call won't block when
  *  results aren't ready, but will immediately return 0.
- *  (A special value of -1 returns 0 unless a ray is
- *  ready in the queue and no system calls are needed.)
  *  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
+ *  queue is completely empty.  Setting the second argument
+ *  to -1 returns 0 unless a ray is ready in the queue and
+ *  no system calls are needed.  A negative return value
  *  indicates that a rendering process died.  If this
  *  happens, ray_pclose(0) is automatically called to close
  *  all child processes, and ray_pnprocs is set to zero.
@@ -147,7 +147,7 @@ static const char	RCSid[] = "$Id: raypcalls.c,v 2.25 2
 #include  "selcall.h"
 
 #ifndef RAYQLEN
-#define RAYQLEN		12		/* # rays to send at once */
+#define RAYQLEN		24		/* # rays to send at once */
 #endif
 
 #ifndef MAX_RPROCS
@@ -164,7 +164,7 @@ 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 */
+	RT_PID	pid;				/* child process id */
 	int	fd_send;			/* write to child here */
 	int	fd_recv;			/* read from child here */
 	int	npending;			/* # rays in process */
@@ -176,6 +176,8 @@ static int	r_send_next = 0;	/* next send ray placement
 static int	r_recv_first = RAYQLEN;	/* position of first unreported ray */
 static int	r_recv_next = RAYQLEN;	/* next received ray placement */
 
+static int	samplestep = 1;		/* sample step size */
+
 #define sendq_full()	(r_send_next >= RAYQLEN)
 
 static int ray_pflush(void);
@@ -210,7 +212,7 @@ ray_pflush(void)			/* send queued rays to idle childre
 	for (i = ray_pnprocs; nc && i--; ) {
 		if (r_proc[i].npending > 0)
 			continue;	/* child looks busy */
-		n = (r_send_next - sfirst)/nc--;
+		n = (r_send_next - sfirst) / nc--;
 		if (!n)
 			continue;
 					/* smuggle set size in crtype */
@@ -288,7 +290,7 @@ ray_presult(		/* check for a completed ray */
 	static struct timeval	tpoll;	/* zero timeval struct */
 	static fd_set	readset, errset;
 	int	n, ok;
-	register int	pn;
+	int	pn;
 
 	if (r == NULL)
 		return(0);
@@ -366,7 +368,7 @@ getready:				/* any children waiting for us? */
 	}
 					/* preen returned rays */
 	for (n = r_recv_next - r_recv_first; n--; ) {
-		register RAY	*rp = &r_queue[r_recv_first + n];
+		RAY	*rp = &r_queue[r_recv_first + n];
 		rp->rno = r_proc[pn].rno[n];
 		rp->parent = NULL;
 		rp->newcset = rp->clipset = NULL;
@@ -402,7 +404,7 @@ ray_pchild(	/* process rays (never returns) */
 )
 {
 	int	n;
-	register int	i;
+	int	i;
 					/* flag child process for quit() */
 	ray_pnprocs = -1;
 					/* read each ray request set */
@@ -428,7 +430,7 @@ ray_pchild(	/* process rays (never returns) */
 			r_queue[i].clipset = NULL;
 			r_queue[i].slights = NULL;
 			r_queue[i].rlvl = 0;
-			samplendx++;
+			samplendx += samplestep;
 			rayclear(&r_queue[i]);
 			rayvalue(&r_queue[i]);
 		}
@@ -462,6 +464,7 @@ ray_popen(			/* open the specified # processes */
 		strcpy(shm_boundary, "SHM_BOUNDARY");
 	}
 	fflush(NULL);			/* clear pending output */
+	samplestep = ray_pnprocs + nadd;
 	while (nadd--) {		/* fork each new process */
 		int	p0[2], p1[2];
 		if (pipe(p0) < 0 || pipe(p1) < 0)
@@ -480,6 +483,10 @@ ray_popen(			/* open the specified # processes */
 		if (r_proc[ray_pnprocs].pid < 0)
 			error(SYSTEM, "cannot fork child process");
 		close(p1[0]); close(p0[1]);
+		if (rand_samp)		/* decorrelate random sequence */
+			srandom(random());
+		else
+			samplendx++;
 		/*
 		 * Close write stream on exec to avoid multiprocessing deadlock.
 		 * No use in read stream without it, so set flag there as well.
@@ -501,11 +508,15 @@ ray_pclose(		/* close one or more child processes */
 )
 {
 	static int	inclose = 0;
-	RAY	res;
+	RAY		res;
+	int		i, status = 0;
 					/* check recursion */
 	if (inclose)
 		return;
 	inclose++;
+					/* check no child / in child */
+	if (ray_pnprocs <= 0)
+		return;
 					/* check argument */
 	if ((nsub <= 0) | (nsub > ray_pnprocs))
 		nsub = ray_pnprocs;
@@ -514,21 +525,31 @@ ray_pclose(		/* close one or more child processes */
 		;
 	r_send_next = 0;		/* hard reset in case of error */
 	r_recv_first = r_recv_next = RAYQLEN;
-					/* clean up children */
-	while (nsub--) {
-		int	status;
-		ray_pnprocs--;
-		close(r_proc[ray_pnprocs].fd_send);
-		if (waitpid(r_proc[ray_pnprocs].pid, &status, 0) < 0)
+					/* close send pipes */
+	for (i = ray_pnprocs-nsub; i < ray_pnprocs; i++)
+		close(r_proc[i].fd_send);
+
+	if (nsub == 1) {		/* awaiting single process? */
+		if (waitpid(r_proc[ray_pnprocs-1].pid, &status, 0) < 0)
 			status = 127<<8;
-		close(r_proc[ray_pnprocs].fd_recv);
-		if (status) {
-			sprintf(errmsg,
-				"rendering process %d exited with code %d",
-					r_proc[ray_pnprocs].pid, status>>8);
-			error(WARNING, errmsg);
+		close(r_proc[ray_pnprocs-1].fd_recv);
+	} else				/* else unordered wait */
+		for (i = 0; i < nsub; ) {
+			int	j, mystatus;
+			RT_PID	pid = wait(&mystatus);
+			for (j = ray_pnprocs-nsub; j < ray_pnprocs; j++)
+				if (r_proc[j].pid == pid) {
+					if (mystatus)
+						status = mystatus;
+					close(r_proc[j].fd_recv);
+					++i;
+				}
 		}
-		ray_pnidle--;
+	ray_pnprocs -= nsub;
+	ray_pnidle -= nsub;
+	if (status) {
+		sprintf(errmsg, "rendering process exited with code %d", status>>8);
+		error(WARNING, errmsg);
 	}
 	inclose--;
 }