Rewrite to remove dependence on rendezvous and its bizarre

data structures.  Makes it easier to use pthreads too.
Still need to add code for non-pthreads systems.

Just a checkpoint to switch work to another machine.

bin/9l

@@ -10,7 +10,7 @@ case "$tag" in
 		extralibs="$extralibs -lutil"
 		;;
 *Linux*)	ld=gcc
-		extralibs="$extralibs -lutil"
+		extralibs="$extralibs -lutil -lpthread"
 		;;
 *Darwin*)	ld=gcc ;;
 *SunOS*)	ld="${CC9:-cc} -g"

include/libc.h

@@ -425,22 +425,49 @@ extern	void	needstack(int);
 /*
  *  synchronization
  */
-typedef
-struct Lock {
-	int	val;
-} Lock;
-
-extern int	_tas(int*);
+typedef struct Lock Lock;
+struct Lock
+{
+#ifdef PLAN9_PTHREADS
+	int init;
+	pthread_mutex_t mutex;
+#else
+	int val;
+#endif
+};
 
 extern	void	lock(Lock*);
 extern	void	unlock(Lock*);
 extern	int	canlock(Lock*);
 
+/*
+ * Used to implement process sleep and wakeup,
+ * either in terms of pthreads or our own primitives.
+ * This will be more portable than writing our own
+ * per-system implementations, and on some systems
+ * non-pthreads threading implementations break libc
+ * (cough, Linux, cough).
+ */
+typedef struct _Procrend _Procrend;
+struct _Procrend
+{
+	int asleep;
+	Lock *l;
+	void *arg;
+#ifdef PLAN9_PTHREADS
+	pthread_cond_t cond;
+#endif
+};
+
+extern	void	_procsleep(_Procrend*);
+extern	void	_procwakeup(_Procrend*);
+
 typedef struct QLp QLp;
 struct QLp
 {
-	int	inuse;
+	Lock	inuse;
 	QLp	*next;
+	_Procrend rend;
 	char	state;
 };
 
@@ -456,7 +483,7 @@ struct QLock
 extern	void	qlock(QLock*);
 extern	void	qunlock(QLock*);
 extern	int	canqlock(QLock*);
-extern	void	_qlockinit(ulong (*)(ulong, ulong));	/* called only by the thread library */
+extern	void	_qlockinit(void(*)(_Procrend*), void(*)(_Procrend*));	/* called only by the thread library */
 
 typedef
 struct RWLock

include/thread.h

@@ -55,7 +55,7 @@ struct Alt {
 	/* the next variables are used internally to alt
 	 * they need not be initialized
 	 */
-	Channel	**tag;	/* pointer to rendez-vous tag */
+	struct Thread	*thread;	/* thread waiting on this alt */
 	int		entryno;	/* entry number */
 };
 

include/u.h

@@ -41,6 +41,8 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #		undef _NEEDUSHORT
 #		undef _NEEDUINT
 #		undef _NEEDULONG
+#	include <pthread.h>
+#	define PLAN9_PTHREADS
 #	endif
 #endif
 #if defined(__sun__)
@@ -48,6 +50,8 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	undef _NEEDULONG
+#	include <pthread.h>
+#	define PLAN9_PTHREADS
 #endif
 #if defined(__FreeBSD__)
 #	include <sys/types.h>
@@ -61,8 +65,11 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	define _NEEDLL 1
+#	include <pthread.h>
+#	define PLAN9_PTHREADS
 #endif
 
+
 typedef signed char schar;
 typedef unsigned int u32int;
 typedef int s32int;

src/lib9/ffork-Linux.c

@@ -1,3 +1,6 @@
+#include "ffork-pthread.c"
+
+#ifdef OLD
 /*
  * Is nothing simple?
  *
@@ -191,3 +194,4 @@ getfforkid(void)
 	return getpid();
 }
 
+#endif

src/lib9/lock.c

@@ -2,52 +2,54 @@
 #include <unistd.h>
 #include <sys/time.h>
 #include <sched.h>
+#include <errno.h>
 #include <libc.h>
 
-int _ntas;
-static int
-_xtas(void *v)
-{
-	int x;
+static pthread_mutex_t initmutex = PTHREAD_MUTEX_INITIALIZER;
 
-	_ntas++;
-	x = _tas(v);
-	return x;
-}
-
-int
-canlock(Lock *l)
+static void
+lockinit(Lock *lk)
 {
-	return !_xtas(&l->val);
-}
+	pthread_mutexattr_t attr;
 
-void
-unlock(Lock *l)
-{
-	l->val = 0;
+	pthread_mutex_lock(&initmutex);
+	if(lk->init == 0){
+		pthread_mutexattr_init(&attr);
+		pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
+		pthread_mutex_init(&lk->mutex, &attr);
+		pthread_mutexattr_destroy(&attr);
+		lk->init = 1;
+	}
+	pthread_mutex_unlock(&initmutex);
 }
 
 void
 lock(Lock *lk)
 {
-	int i;
-
-	/* once fast */
-	if(!_xtas(&lk->val))
-		return;
-	/* a thousand times pretty fast */
-	for(i=0; i<1000; i++){
-		if(!_xtas(&lk->val))
-			return;
-		sched_yield();
-	}
-	/* now nice and slow */
-	for(i=0; i<1000; i++){
-		if(!_xtas(&lk->val))
-			return;
-		usleep(100*1000);
-	}
-	/* take your time */
-	while(_xtas(&lk->val))
-		usleep(1000*1000);
+	if(!lk->init)
+		lockinit(lk);
+	if(pthread_mutex_lock(&lk->mutex) != 0)
+		abort();
+}
+
+int
+canlock(Lock *lk)
+{
+	int r;
+
+	if(!lk->init)
+		lockinit(lk);
+	r = pthread_mutex_trylock(&lk->mutex);
+	if(r == 0)
+		return 1;
+	if(r == EBUSY)
+		return 0;
+	abort();
+}
+
+void
+unlock(Lock *lk)
+{
+	if(pthread_mutex_unlock(&lk->mutex) != 0)
+		abort();
 }

src/lib9/qlock.c

@@ -16,13 +16,15 @@ enum
 	Waking,
 };
 
-static ulong	(*_rendezvousp)(ulong, ulong) = rendezvous;
+static void (*procsleep)(_Procrend*) = _procsleep;
+static void (*procwakeup)(_Procrend*) = _procwakeup;
 
 /* this gets called by the thread library ONLY to get us to use its rendezvous */
 void
-_qlockinit(ulong (*r)(ulong, ulong))
+_qlockinit(void (*sleep)(_Procrend*), void (*wakeup)(_Procrend*))
 {
-	_rendezvousp = r;
+	procsleep = sleep;
+	procwakeup = wakeup;
 }
 
 /* find a free shared memory location to queue ourselves in */
@@ -39,7 +41,7 @@ getqlp(void)
 			fprint(2, "qlock: out of qlp\n");
 			abort();
 		}
-		if(_tas(&(p->inuse)) == 0){
+		if(canlock(&p->inuse)){
 			ql.p = p;
 			p->next = nil;
 			break;
@@ -70,13 +72,11 @@ qlock(QLock *q)
 		p->next = mp;
 	q->tail = mp;
 	mp->state = Queuing;
+	mp->rend.l = &q->lock;
+	_procsleep(&mp->rend);
 	unlock(&q->lock);
-
-	/* wait */
-	while((*_rendezvousp)((ulong)mp, 1) == ~0)
-		;
 	assert(mp->state == Waking);
-	mp->inuse = 0;
+	unlock(&mp->inuse);
 }
 
 void
@@ -91,10 +91,9 @@ qunlock(QLock *q)
 		q->head = p->next;
 		if(q->head == nil)
 			q->tail = nil;
-		unlock(&q->lock);
 		p->state = Waking;
-		while((*_rendezvousp)((ulong)p, 0x12345) == ~0)
-			;
+		_procwakeup(&p->rend);
+		unlock(&q->lock);
 		return;
 	}
 	q->locked = 0;
@@ -137,13 +136,11 @@ rlock(RWLock *q)
 	q->tail = mp;
 	mp->next = nil;
 	mp->state = QueuingR;
+	mp->rend.l = &q->lock;
+	_procsleep(&mp->rend);
 	unlock(&q->lock);
-
-	/* wait in kernel */
-	while((*_rendezvousp)((ulong)mp, 1) == ~0)
-		;
 	assert(mp->state == Waking);
-	mp->inuse = 0;
+	unlock(&mp->inuse);
 }
 
 int
@@ -181,12 +178,11 @@ runlock(RWLock *q)
 	if(q->head == 0)
 		q->tail = 0;
 	q->writer = 1;
-	unlock(&q->lock);
 
 	/* wakeup waiter */
 	p->state = Waking;
-	while((*_rendezvousp)((ulong)p, 0) == ~0)
-		;
+	_procwakeup(&p->rend);
+	unlock(&q->lock);
 }
 
 void
@@ -212,13 +208,13 @@ wlock(RWLock *q)
 	q->tail = mp;
 	mp->next = nil;
 	mp->state = QueuingW;
-	unlock(&q->lock);
 
 	/* wait in kernel */
-	while((*_rendezvousp)((ulong)mp, 1) == ~0)
-		;
+	mp->rend.l = &q->lock;
+	_procsleep(&mp->rend);
+	unlock(&q->lock);
 	assert(mp->state == Waking);
-	mp->inuse = 0;
+	unlock(&mp->inuse);
 }
 
 int
@@ -256,10 +252,9 @@ wunlock(RWLock *q)
 		q->head = p->next;
 		if(q->head == nil)
 			q->tail = nil;
-		unlock(&q->lock);
 		p->state = Waking;
-		while((*_rendezvousp)((ulong)p, 0) == ~0)
-			;
+		_procwakeup(&p->rend);
+		unlock(&q->lock);
 		return;
 	}
 
@@ -274,8 +269,7 @@ wunlock(RWLock *q)
 		q->head = p->next;
 		q->readers++;
 		p->state = Waking;
-		while((*_rendezvousp)((ulong)p, 0) == ~0)
-			;
+		_procwakeup(&p->rend);
 	}
 	if(q->head == nil)
 		q->tail = nil;
@@ -315,20 +309,17 @@ rsleep(Rendez *r)
 		r->l->head = t->next;
 		if(r->l->head == nil)
 			r->l->tail = nil;
-		unlock(&r->l->lock);
 		t->state = Waking;
-		while((*_rendezvousp)((ulong)t, 0x12345) == ~0)
-			;
-	}else{
+		_procwakeup(&t->rend);
+	}else
 		r->l->locked = 0;
-		unlock(&r->l->lock);
-	}
 
 	/* wait for a wakeup */
-	while((*_rendezvousp)((ulong)me, 0x23456) == ~0)
-		;
+	me->rend.l = &r->l->lock;
+	_procsleep(&me->rend);
+
 	assert(me->state == Waking);
-	me->inuse = 0;
+	unlock(&me->inuse);
 	if(!r->l->locked){
 		fprint(2, "rsleep: not locked after wakeup\n");
 		abort();
@@ -384,3 +375,23 @@ rwakeupall(Rendez *r)
 		;
 	return i;
 }
+
+void
+_procsleep(_Procrend *rend)
+{
+//print("sleep %p %d\n", rend, getpid());
+	pthread_cond_init(&rend->cond, 0);
+	rend->asleep = 1;
+	while(rend->asleep)
+		pthread_cond_wait(&rend->cond, &rend->l->mutex);
+	pthread_cond_destroy(&rend->cond);
+}
+
+void
+_procwakeup(_Procrend *rend)
+{
+//print("wakeup %p\n", rend);
+	rend->asleep = 0;
+	pthread_cond_signal(&rend->cond);
+}
+

src/libthread/channel.c

@@ -2,7 +2,7 @@
 
 static Lock chanlock;		/* central channel access lock */
 
-static void enqueue(Alt*, Channel**);
+static void enqueue(Alt*, Thread*);
 static void dequeue(Alt*);
 static int altexec(Alt*, int);
 
@@ -29,7 +29,7 @@ canexec(Alt *a)
 	/* are there senders or receivers blocked? */
 	otherop = (CHANSND+CHANRCV) - a->op;
 	for(i=0; i<c->nentry; i++)
-		if(c->qentry[i] && c->qentry[i]->op==otherop && *c->qentry[i]->tag==nil){
+		if(c->qentry[i] && c->qentry[i]->op==otherop && c->qentry[i]->thread==nil){
 			_threaddebug(DBGCHAN, "can rendez alt %p chan %p", a, c);
 			return 1;
 		}
@@ -100,9 +100,8 @@ static int
 _alt(Alt *alts)
 {
 	Alt *a, *xa;
-	Channel *volatile c;
+	Channel *c;
 	int n, s;
-	ulong r;
 	Thread *t;
 
 	/*
@@ -153,11 +152,11 @@ _threadnalt++;
 		}
 
 		/* enqueue on all channels. */
-		c = nil;
+		t->altc = nil;
 		for(xa=alts; xa->op!=CHANEND; xa++){
 			if(xa->op==CHANNOP)
 				continue;
-			enqueue(xa, (Channel**)&c);
+			enqueue(xa, t);
 		}
 
 		/*
@@ -166,25 +165,20 @@ _threadnalt++;
 		 * is interrupted -- someone else might come
 		 * along and try to rendezvous with us, so
 		 * we need to be here.
+		 *
+		 * actually, now we're assuming no interrupts.
 		 */
-	    Again:
+	    /*Again:*/
 		t->alt = alts;
 		t->chan = Chanalt;
-
-		unlock(&chanlock);
+		t->altrend.l = &chanlock;
 		_procsplx(s);
-		r = _threadrendezvous((ulong)&c, 0);
+		_threadsleep(&t->altrend);
 		s = _procsplhi();
-		lock(&chanlock);
-
-		if(r==~0){		/* interrupted */
-			if(c!=nil)		/* someone will meet us; go back */
-				goto Again;
-			c = (Channel*)~0;	/* so no one tries to meet us */
-		}
 
 		/* dequeue from channels, find selected one */
 		a = nil;
+		c = t->altc;
 		for(xa=alts; xa->op!=CHANEND; xa++){
 			if(xa->op==CHANNOP)
 				continue;
@@ -385,12 +379,12 @@ if(c->nentry > _threadhighnentry) _threadhighnentry = c->nentry;
 }
 
 static void
-enqueue(Alt *a, Channel **c)
+enqueue(Alt *a, Thread *t)
 {
 	int i;
 
 	_threaddebug(DBGCHAN, "Queueing alt %p on channel %p", a, a->c);
-	a->tag = c;
+	a->thread = t;
 	i = emptyentry(a->c);
 	a->c->qentry[i] = a;
 }
@@ -466,7 +460,7 @@ altexec(Alt *a, int spl)
 	b = nil;
 	me = a->v;
 	for(i=0; i<c->nentry; i++)
-		if(c->qentry[i] && c->qentry[i]->op==otherop && *c->qentry[i]->tag==nil)
+		if(c->qentry[i] && c->qentry[i]->op==otherop && c->qentry[i]->thread==nil)
 			if(nrand(++n) == 0)
 				b = c->qentry[i];
 	if(b != nil){
@@ -493,13 +487,12 @@ altexec(Alt *a, int spl)
 			else
 				altcopy(waiter, me, c->e);
 		}
-		*b->tag = c;	/* commits us to rendezvous */
+		b->thread->altc = c;
+		_procwakeup(&b->thread->altrend);
+		_threaddebug(DBGCHAN, "chanlock is %lud", *(ulong*)(void*)&chanlock);
 		_threaddebug(DBGCHAN, "unlocking the chanlock");
 		unlock(&chanlock);
 		_procsplx(spl);
-		_threaddebug(DBGCHAN, "chanlock is %lud", *(ulong*)(void*)&chanlock);
-		while(_threadrendezvous((ulong)b->tag, 0) == ~0)
-			;
 		return 1;
 	}
 

src/libthread/create.c

@@ -2,6 +2,7 @@
 
 Pqueue _threadpq;
 int _threadprocs;
+int __pthread_nonstandard_stacks;
 
 static int nextID(void);
 
@@ -21,6 +22,7 @@ newthread(Proc *p, void (*f)(void *arg), void *arg, uint stacksize, char *name,
 	Thread *t;
 	char *s;
 
+	__pthread_nonstandard_stacks = 1;
 	if(stacksize < 32)
 		sysfatal("bad stacksize %d", stacksize);
 	t = _threadmalloc(sizeof(Thread), 1);

src/libthread/main.c

@@ -40,7 +40,7 @@ main(int argc, char **argv)
 
 //_threaddebuglevel = (DBGSCHED|DBGCHAN|DBGREND)^~0;
 	_systhreadinit();
-	_qlockinit(_threadrendezvous);
+	_qlockinit(_threadsleep, _threadwakeup);
 	_sysfatal = _threadsysfatal;
 	notify(_threadnote);
 	if(mainstacksize == 0)
@@ -49,8 +49,9 @@ main(int argc, char **argv)
 	a = _threadmalloc(sizeof *a, 1);
 	a->argc = argc;
 	a->argv = argv;
-
+malloc(10);
 	p = _newproc(mainlauncher, a, mainstacksize, "threadmain", 0, 0);
+malloc(10);
 	_schedinit(p);
 	abort();	/* not reached */
 	return 0;
@@ -61,7 +62,9 @@ mainlauncher(void *arg)
 {
 	Mainarg *a;
 
+malloc(10);
 	a = arg;
+malloc(10);
 	threadmain(a->argc, a->argv);
 	threadexits("threadmain");
 }

src/libthread/mkfile

@@ -23,7 +23,6 @@ OFILES=\
 	ioreadn.$O\
 	iosleep.$O\
 	iowrite.$O\
-	kill.$O\
 	lib.$O\
 	main.$O\
 	memset.$O\
@@ -43,13 +42,13 @@ HFILES=\
 <$PLAN9/src/mksyslib
 
 tprimes: tprimes.$O $PLAN9/lib/$LIB
-	$LD -o tprimes tprimes.$O $LDFLAGS -lthread -l9 -lfmt -lutf
+	$LD -o tprimes tprimes.$O $LDFLAGS -lthread -l9
 
 texec: texec.$O $PLAN9/lib/$LIB
-	$LD -o texec texec.$O $LDFLAGS -lthread -l9 -lfmt -lutf
+	$LD -o texec texec.$O $LDFLAGS -lthread -l9
 
 trend: trend.$O $PLAN9/lib/$LIB
-	$LD -o trend trend.$O $LDFLAGS -lthread -l9 -lfmt -lutf
+	$LD -o trend trend.$O $LDFLAGS -lthread -l9
 
 CLEANFILES=$CLEANFILES tprimes texec
 

src/libthread/rendez.c

@@ -1,104 +1,38 @@
 #include "threadimpl.h"
 
-Rgrp _threadrgrp;
-static int isdirty;
 int _threadhighnrendez;
 int _threadnrendez;
-static int nrendez;
 
-static ulong
-finish(Thread *t, ulong val)
+void
+_threadsleep(_Procrend *r)
 {
-	ulong ret;
+	Thread *t;
 
-	ret = t->rendval;
-	t->rendval = val;
+	t = _threadgetproc()->thread;
+	r->arg = t;
+	t->nextstate = Rendezvous;
+	t->inrendez = 1;
+	unlock(r->l);
+	_sched();
+	t->inrendez = 0;
+	lock(r->l);
+}
+
+void
+_threadwakeup(_Procrend *r)
+{
+	Thread *t;
+
+	t = r->arg;
 	while(t->state == Running)
 		sleep(0);
 	lock(&t->proc->lock);
-	if(t->state == Rendezvous){	/* not always true: might be Dead */
-		t->state = Ready;
-		_threadready(t);
+	if(t->state == Dead){
+		unlock(&t->proc->lock);
+		return;
 	}
+	assert(t->state == Rendezvous && t->inrendez);
+	t->state = Ready;
+	_threadready(t);
 	unlock(&t->proc->lock);
-	return ret;
-}
-
-ulong
-_threadrendezvous(ulong tag, ulong val)
-{
-	ulong ret;
-	Thread *t, **l;
-
-	lock(&_threadrgrp.lock);
-_threadnrendez++;
-	l = &_threadrgrp.hash[tag%nelem(_threadrgrp.hash)];
-	for(t=*l; t; l=&t->rendhash, t=*l){
-		if(t->rendtag==tag){
-			_threaddebug(DBGREND, "Rendezvous with thread %d.%d", t->proc->pid, t->id);
-			*l = t->rendhash;
-			ret = finish(t, val);
-			--nrendez;
-			unlock(&_threadrgrp.lock);
-			return ret;
-		}
-	}
-
-	/* Going to sleep here. */
-	t = _threadgetproc()->thread;
-	t->rendbreak = 0;
-	t->inrendez = 1;
-	t->rendtag = tag;
-	t->rendval = val;
-	t->rendhash = *l;
-	*l = t;
-	++nrendez;
-	if(nrendez > _threadhighnrendez)
-		_threadhighnrendez = nrendez;
-	_threaddebug(DBGREND, "Rendezvous for tag %lud (m=%d)", t->rendtag, t->moribund);
-	unlock(&_threadrgrp.lock);
-	t->nextstate = Rendezvous;
-	_sched();
-	t->inrendez = 0;
-	_threaddebug(DBGREND, "Woke after rendezvous; val is %lud", t->rendval);
-	return t->rendval;
-}
-
-/*
- * This is called while holding _threadpq.lock and p->lock,
- * so we can't lock _threadrgrp.lock.  Instead our caller has 
- * to call _threadbreakrendez after dropping those locks.
- */
-void
-_threadflagrendez(Thread *t)
-{
-	t->rendbreak = 1;
-	isdirty = 1;
-}
-
-void
-_threadbreakrendez(void)
-{
-	int i;
-	Thread *t, **l;
-
-	if(isdirty == 0)
-		return;
-	lock(&_threadrgrp.lock);
-	if(isdirty == 0){
-		unlock(&_threadrgrp.lock);
-		return;
-	}
-	isdirty = 0;
-	for(i=0; i<nelem(_threadrgrp.hash); i++){
-		l = &_threadrgrp.hash[i];
-		for(t=*l; t; t=*l){
-			if(t->rendbreak){
-				*l = t->rendhash;
-				finish(t, ~0);
-			}else
-				 l=&t->rendhash;
-		}
-	}
-	unlock(&_threadrgrp.lock);
 }

src/libthread/sched.c

@@ -36,6 +36,7 @@ _schedinit(void *arg)
 	unlock(&p->lock);
 	while(_setlabel(&p->sched))
 		;
+malloc(10);
 	_threaddebug(DBGSCHED, "top of schedinit, _threadexitsallstatus=%p", _threadexitsallstatus);
 	if(_threadexitsallstatus)
 		_exits(_threadexitsallstatus);
@@ -57,8 +58,9 @@ _schedinit(void *arg)
 				p->threads.tail = t->prevt;
 			unlock(&p->lock);
 			if(t->inrendez){
-				_threadflagrendez(t);
-				_threadbreakrendez();
+				abort();
+			//	_threadflagrendez(t);
+			//	_threadbreakrendez();
 			}
 			_stackfree(t->stk);
 			free(t->cmdname);
@@ -183,15 +185,18 @@ _sched(void)
 Resched:
 	p = _threadgetproc();
 //fprint(2, "p %p\n", p);
+malloc(10);
 	if((t = p->thread) != nil){
 		needstack(512);
 	//	_threaddebug(DBGSCHED, "pausing, state=%s set %p goto %p",
 	//		psstate(t->state), &t->sched, &p->sched);
+print("swap\n");
 		if(_setlabel(&t->sched)==0)
 			_gotolabel(&p->sched);
 		_threadstacklimit(t->stk, t->stk+t->stksize);
 		return p->nsched++;
 	}else{
+malloc(10);
 		t = runthread(p);
 		if(t == nil){
 			_threaddebug(DBGSCHED, "all threads gone; exiting");
@@ -206,6 +211,8 @@ Resched:
 		}
 		t->state = Running;
 		t->nextstate = Ready;
+malloc(10);
+print("gotolabel\n");
 		_gotolabel(&t->sched);
 		for(;;);
 	}

src/libthread/threadimpl.h

@@ -89,10 +89,8 @@ struct Thread
 	char		*cmdname;	/* ptr to name of thread */
 
 	int		inrendez;	
-	Thread	*rendhash;	/* Trgrp linked list */
-	ulong	rendtag;		/* rendezvous tag */
-	ulong	rendval;		/* rendezvous value */
-	int		rendbreak;	/* rendezvous has been taken */
+	Channel	*altc;
+	_Procrend	altrend;
 
 	Chanstate	chan;		/* which channel operation is current */
 	Alt		*alt;			/* pointer to current alt structure (debugging) */
@@ -179,11 +177,9 @@ int		_schedfork(Proc*);
 void		_schedinit(void*);
 void		_systhreadinit(void);
 void		_threadassert(char*);
-void		_threadbreakrendez(void);
 void		__threaddebug(ulong, char*, ...);
 #define _threaddebug if(!_threaddebuglevel){}else __threaddebug
 void		_threadexitsall(char*);
-void		_threadflagrendez(Thread*);
 Proc*	_threadgetproc(void);
 extern void	_threadmultiproc(void);
 Proc*	_threaddelproc(void);
@@ -193,7 +189,8 @@ void*	_threadmalloc(long, int);
 void		_threadnote(void*, char*);
 void		_threadready(Thread*);
 void		_threadidle(void);
-ulong	_threadrendezvous(ulong, ulong);
+void		_threadsleep(_Procrend*);
+void		_threadwakeup(_Procrend*);
 void		_threadsignal(void);
 void		_threadsysfatal(char*, va_list);
 long		_xdec(long*);

src/libthread/tprimes.c

@@ -41,6 +41,7 @@ threadmain(int argc, char **argv)
 	int i;
 	Channel *c;
 
+malloc(10);
 	ARGBEGIN{
 	case 'D':
 		_threaddebuglevel = atoi(ARGF());