Commit be72dc05 authored by sof's avatar sof

[project @ 2002-02-04 20:40:36 by sof]

Snapshot of 'native thread'-friendly extension:
- call-outs now work, i.e., a Concurrent Haskell thread which
  makes an external (C) call no longer stop other CH threads
  dead in their tracks. [More testing and tightening up of
  invariants reqd, this is just a snapshot].
- separated task handling into sep. module.
parent cc517f07
/* ---------------------------------------------------------------------------
* $Id: Schedule.c,v 1.114 2002/01/31 11:18:07 sof Exp $
* $Id: Schedule.c,v 1.115 2002/02/04 20:40:36 sof Exp $
*
* (c) The GHC Team, 1998-2000
*
......@@ -112,6 +112,7 @@
#include "Sparks.h"
#include "Capability.h"
#include "OSThreads.h"
#include "Task.h"
#include <stdarg.h>
......@@ -138,7 +139,7 @@ typedef struct StgMainThread_ {
SchedulerStatus stat;
StgClosure ** ret;
#if defined(RTS_SUPPORTS_THREADS)
CondVar wakeup;
Condition wakeup;
#endif
struct StgMainThread_ *link;
} StgMainThread;
......@@ -228,10 +229,6 @@ StgThreadID next_thread_id = 1;
#define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
#if !defined(SMP)
Capability MainCapability; /* for non-SMP, we have one global capability */
#endif
#if defined(GRAN)
StgTSO *CurrentTSO;
#endif
......@@ -244,13 +241,6 @@ StgTSO dummy_tso;
rtsBool ready_to_gc;
/* All our current task ids, saved in case we need to kill them later.
*/
#if defined(SMP)
//@cindex task_ids
task_info *task_ids;
#endif
void addToBlockedQueue ( StgTSO *tso );
static void schedule ( void );
......@@ -271,10 +261,56 @@ static void sched_belch(char *s, ...);
/* ToDo: carefully document the invariants that go together
* with these synchronisation objects.
*/
MutexVar sched_mutex = INIT_MUTEX_VAR;
MutexVar term_mutex = INIT_MUTEX_VAR;
CondVar thread_ready_cond = INIT_COND_VAR;
CondVar gc_pending_cond = INIT_COND_VAR;
Mutex sched_mutex = INIT_MUTEX_VAR;
Mutex term_mutex = INIT_MUTEX_VAR;
#if defined(THREADED_RTS)
/*
* The rts_mutex is the 'big lock' that the active native
* thread within the RTS holds while executing code
* within the RTS. It is given up when the thread makes a
* transition out of the RTS (e.g., to perform an external
* C call), hopefully for another thread to enter the RTS.
*
*/
Mutex rts_mutex = INIT_MUTEX_VAR;
/*
* When a native thread has completed executing an external
* call, it needs to communicate the result back to the
* (Haskell) thread that made the call. Do this as follows:
*
* - in resumeThread(), the thread increments the counter
* ext_threads_waiting, and then blocks on the
* 'big' RTS lock.
* - upon entry to the scheduler, the thread that's currently
* holding the RTS lock checks ext_threads_waiting. If there
* are native threads waiting, it gives up its RTS lock
* and tries to re-grab the RTS lock [perhaps after having
* waited for a bit..?]
* - care must be taken to deal with the case where more than
* one external thread are waiting on the lock. [ToDo: more]
*
*/
static nat ext_threads_waiting = 0;
/*
* thread_ready_aux_mutex is used to handle the scenario where the
* the RTS executing thread runs out of work, but there are
* active external threads. The RTS executing thread gives up
* its RTS mutex, and blocks waiting for the thread_ready_cond.
* Unfortunately, a condition variable needs to be associated
* with a mutex in pthreads, so rts_thread_waiting_mutex is
* used for just this purpose.
*
*/
Mutex thread_ready_aux_mutex = INIT_MUTEX_VAR;
#endif
/* thread_ready_cond: when signalled, a thread has
* become runnable. When used?
*/
Condition thread_ready_cond = INIT_COND_VAR;
Condition gc_pending_cond = INIT_COND_VAR;
nat await_death;
#endif
......@@ -314,6 +350,23 @@ StgTSO * activateSpark (rtsSpark spark);
StgTSO *MainTSO;
*/
#if defined(PAR) || defined(RTS_SUPPORTS_THREADS)
static void taskStart(void);
static void
taskStart(void)
{
/* threads start up using 'taskStart', so make them
them grab the RTS lock. */
#if defined(THREADED_RTS)
ACQUIRE_LOCK(&rts_mutex);
#endif
schedule();
}
#endif
//@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
//@subsection Main scheduling loop
......@@ -374,6 +427,25 @@ schedule( void )
rtsBool was_interrupted = rtsFalse;
ACQUIRE_LOCK(&sched_mutex);
#if defined(THREADED_RTS)
/* ToDo: consider SMP support */
if (ext_threads_waiting > 0) {
/* (At least) one external thread is waiting to
* to deposit the result of an external call.
* Give way to one of them by giving up the RTS
* lock.
*/
RELEASE_LOCK(&sched_mutex);
RELEASE_LOCK(&rts_mutex);
/* ToDo: come up with mechanism that guarantees that
* the main thread doesn't loop here.
*/
yieldThread();
/* ToDo: longjmp() */
taskStart();
}
#endif
#if defined(GRAN)
......@@ -439,7 +511,7 @@ schedule( void )
}
*prev = m->link;
m->stat = Success;
broadcastCondVar(&m->wakeup);
broadcastCondition(&m->wakeup);
break;
case ThreadKilled:
if (m->ret) *(m->ret) = NULL;
......@@ -449,7 +521,7 @@ schedule( void )
} else {
m->stat = Killed;
}
broadcastCondVar(&m->wakeup);
broadcastCondition(&m->wakeup);
break;
default:
break;
......@@ -525,7 +597,7 @@ schedule( void )
* work for them.
*/
if (getFreeCapabilities() - n > 1) {
signalCondVar ( &thread_ready_cond );
signalCondition( &thread_ready_cond );
}
}
#endif // SMP
......@@ -571,11 +643,16 @@ schedule( void )
&& sleeping_queue == END_TSO_QUEUE
#if defined(SMP)
&& allFreeCapabilities()
#elif defined(THREADED_RTS)
&& suspended_ccalling_threads == END_TSO_QUEUE
#endif
)
{
IF_DEBUG(scheduler, sched_belch("deadlocked, forcing major GC..."));
RELEASE_LOCK(&sched_mutex);
GarbageCollect(GetRoots,rtsTrue);
ACQUIRE_LOCK(&sched_mutex);
IF_DEBUG(scheduler, sched_belch("GC done."));
if (blocked_queue_hd == END_TSO_QUEUE
&& run_queue_hd == END_TSO_QUEUE
&& sleeping_queue == END_TSO_QUEUE) {
......@@ -619,9 +696,14 @@ schedule( void )
}
#endif
}
#if !defined(RTS_SUPPORTS_THREADS)
ASSERT( run_queue_hd != END_TSO_QUEUE );
#if defined(RTS_SUPPORTS_THREADS)
if ( run_queue_hd == END_TSO_QUEUE ) {
IF_DEBUG(scheduler, sched_belch("all done, it seems...shut down."));
shutdownHaskellAndExit(0);
}
#endif
ASSERT( run_queue_hd != END_TSO_QUEUE );
}
}
#elif defined(PAR)
......@@ -634,23 +716,37 @@ schedule( void )
*/
if (ready_to_gc) {
IF_DEBUG(scheduler,sched_belch("waiting for GC"));
waitCondVar ( &gc_pending_cond, &sched_mutex );
waitCondition( &gc_pending_cond, &sched_mutex );
}
#endif
#if defined(RTS_SUPPORTS_THREADS)
#if defined(SMP)
/* block until we've got a thread on the run queue and a free
* capability.
*/
while ( run_queue_hd == END_TSO_QUEUE
#if defined(SMP)
|| noFreeCapabilities()
#endif
) {
IF_DEBUG(scheduler, sched_belch("waiting for work"));
waitCondVar ( &thread_ready_cond, &sched_mutex );
waitCondition( &thread_ready_cond, &sched_mutex );
IF_DEBUG(scheduler, sched_belch("work now available"));
}
#elif defined(THREADED_RTS)
if ( run_queue_hd == END_TSO_QUEUE ) {
/* no work available, wait for external calls to complete. */
IF_DEBUG(scheduler, sched_belch("worker thread (%d): waiting for external thread to complete..", osThreadId()));
RELEASE_LOCK(&sched_mutex);
RELEASE_LOCK(&rts_mutex);
/* Sigh - need to have a mutex locked in order to wait on the
condition variable. */
ACQUIRE_LOCK(&thread_ready_aux_mutex);
waitCondition(&thread_ready_cond, &thread_ready_aux_mutex);
RELEASE_LOCK(&thread_ready_aux_mutex);
IF_DEBUG(scheduler, sched_belch("worker thread (%d): re-awakened from no-work slumber..\n", osThreadId()));
/* ToDo: longjmp() */
taskStart();
}
#endif
#if defined(GRAN)
......@@ -932,19 +1028,12 @@ schedule( void )
*/
ASSERT(run_queue_hd != END_TSO_QUEUE);
t = POP_RUN_QUEUE();
// Sanity check the thread we're about to run. This can be
// expensive if there is lots of thread switching going on...
IF_DEBUG(sanity,checkTSO(t));
#endif
#ifdef SMP
grabCapability(&cap);
#else
cap = &MainCapability;
#endif
cap->r.rCurrentTSO = t;
/* context switches are now initiated by the timer signal, unless
......@@ -1323,7 +1412,7 @@ schedule( void )
GarbageCollect(GetRoots,rtsFalse);
ready_to_gc = rtsFalse;
#ifdef SMP
broadcastCondVar(&gc_pending_cond);
broadcastCondition(&gc_pending_cond);
#endif
#if defined(GRAN)
/* add a ContinueThread event to continue execution of current thread */
......@@ -1381,6 +1470,7 @@ void deleteAllThreads ( void )
/* startThread and insertThread are now in GranSim.c -- HWL */
//@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
//@subsection Suspend and Resume
......@@ -1405,7 +1495,9 @@ suspendThread( StgRegTable *reg )
nat tok;
Capability *cap;
// assume that *reg is a pointer to the StgRegTable part of a Capability
/* assume that *reg is a pointer to the StgRegTable part
* of a Capability.
*/
cap = (Capability *)((void *)reg - sizeof(StgFunTable));
ACQUIRE_LOCK(&sched_mutex);
......@@ -1420,12 +1512,16 @@ suspendThread( StgRegTable *reg )
/* Use the thread ID as the token; it should be unique */
tok = cap->r.rCurrentTSO->id;
#ifdef SMP
/* Hand back capability */
releaseCapability(&cap);
#if defined(RTS_SUPPORTS_THREADS) && !defined(SMP)
IF_DEBUG(scheduler, sched_belch("thread %d leaving RTS\n", tok));
startTask(taskStart);
#endif
RELEASE_LOCK(&sched_mutex);
RELEASE_LOCK(&rts_mutex);
return tok;
}
......@@ -1435,8 +1531,23 @@ resumeThread( StgInt tok )
StgTSO *tso, **prev;
Capability *cap;
IF_DEBUG(scheduler, sched_belch("thread %d returning, waiting for sched. lock.\n", tok));
ACQUIRE_LOCK(&sched_mutex);
ext_threads_waiting++;
IF_DEBUG(scheduler, sched_belch("thread %d returning, ext_thread count: %d.\n", tok, ext_threads_waiting));
RELEASE_LOCK(&sched_mutex);
IF_DEBUG(scheduler, sched_belch("thread %d waiting for RTS lock...\n", tok));
ACQUIRE_LOCK(&rts_mutex);
ext_threads_waiting--;
IF_DEBUG(scheduler, sched_belch("thread %d acquired RTS lock...\n", tok));
#if defined(THREADED_RTS)
/* Free up any RTS-blocked threads. */
broadcastCondition(&thread_ready_cond);
#endif
/* Remove the thread off of the suspended list */
prev = &suspended_ccalling_threads;
for (tso = suspended_ccalling_threads;
tso != END_TSO_QUEUE;
......@@ -1451,20 +1562,18 @@ resumeThread( StgInt tok )
}
tso->link = END_TSO_QUEUE;
#ifdef SMP
#if defined(SMP)
while ( noFreeCapabilities() ) {
IF_DEBUG(scheduler, sched_belch("waiting to resume"));
waitCondVar(&thread_ready_cond, &sched_mutex);
waitCondition(&thread_ready_cond, &sched_mutex);
IF_DEBUG(scheduler, sched_belch("resuming thread %d", tso->id));
}
grabCapability(&cap);
#else
cap = &MainCapability;
#endif
grabCapability(&cap);
cap->r.rCurrentTSO = tso;
RELEASE_LOCK(&sched_mutex);
return &cap->r;
}
......@@ -1788,22 +1897,6 @@ scheduleThread(StgTSO *tso)
RELEASE_LOCK(&sched_mutex);
}
/* ---------------------------------------------------------------------------
* startTasks()
*
* Start up Posix threads to run each of the scheduler tasks.
* I believe the task ids are not needed in the system as defined.
* KH @ 25/10/99
* ------------------------------------------------------------------------ */
#if defined(PAR) || defined(SMP)
void
taskStart(void) /* ( void *arg STG_UNUSED) */
{
schedule();
}
#endif
/* ---------------------------------------------------------------------------
* initScheduler()
*
......@@ -1811,7 +1904,6 @@ taskStart(void) /* ( void *arg STG_UNUSED) */
* queues contained any threads, they'll be garbage collected at the
* next pass.
*
* This now calls startTasks(), so should only be called once! KH @ 25/10/99
* ------------------------------------------------------------------------ */
#ifdef SMP
......@@ -1858,6 +1950,27 @@ initScheduler(void)
RtsFlags.ConcFlags.ctxtSwitchTicks =
RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
#if defined(RTS_SUPPORTS_THREADS)
/* Initialise the mutex and condition variables used by
* the scheduler. */
initMutex(&rts_mutex);
initMutex(&sched_mutex);
initMutex(&term_mutex);
#if defined(THREADED_RTS)
initMutex(&thread_ready_aux_mutex);
#endif
initCondition(&thread_ready_cond);
initCondition(&gc_pending_cond);
#endif
#if defined(THREADED_RTS)
/* Grab big lock */
ACQUIRE_LOCK(&rts_mutex);
IF_DEBUG(scheduler,
sched_belch("worker thread (%d): acquired RTS lock\n", osThreadId()));
#endif
/* Install the SIGHUP handler */
#ifdef SMP
......@@ -1873,11 +1986,19 @@ initScheduler(void)
}
#endif
#ifdef SMP
/* Allocate N Capabilities */
initCapabilities(RtsFlags.ParFlags.nNodes);
#else
initCapability(&MainCapability);
/* A capability holds the state a native thread needs in
* order to execute STG code. At least one capability is
* floating around (only SMP builds have more than one).
*/
initCapabilities();
#if defined(RTS_SUPPORTS_THREADS)
/* start our haskell execution tasks */
# if defined(SMP)
startTaskManager(RtsFlags.ParFlags.nNodes, taskStart);
# else
startTaskManager(0,taskStart);
# endif
#endif
#if /* defined(SMP) ||*/ defined(PAR)
......@@ -1885,68 +2006,11 @@ initScheduler(void)
#endif
}
#ifdef SMP
void
startTasks( void )
{
nat i;
int r;
OSThreadId tid;
/* make some space for saving all the thread ids */
task_ids = stgMallocBytes(RtsFlags.ParFlags.nNodes * sizeof(task_info),
"initScheduler:task_ids");
/* and create all the threads */
for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
r = createOSThread(&tid,taskStart);
if (r != 0) {
barf("startTasks: Can't create new Posix thread");
}
task_ids[i].id = tid;
task_ids[i].mut_time = 0.0;
task_ids[i].mut_etime = 0.0;
task_ids[i].gc_time = 0.0;
task_ids[i].gc_etime = 0.0;
task_ids[i].elapsedtimestart = stat_getElapsedTime();
IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Started task: %ld\n",tid););
}
}
#endif
void
exitScheduler( void )
{
#ifdef SMP
nat i;
/* Don't want to use pthread_cancel, since we'd have to install
* these silly exception handlers (pthread_cleanup_{push,pop}) around
* all our locks.
*/
#if 0
/* Cancel all our tasks */
for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
pthread_cancel(task_ids[i].id);
}
/* Wait for all the tasks to terminate */
for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
IF_DEBUG(scheduler,fprintf(stderr,"scheduler: waiting for task %ld\n",
task_ids[i].id));
pthread_join(task_ids[i].id, NULL);
}
#endif
/* Send 'em all a SIGHUP. That should shut 'em up.
*/
await_death = RtsFlags.ParFlags.nNodes;
for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
pthread_kill(task_ids[i].id,SIGTERM);
}
while (await_death > 0) {
sched_yield();
}
#if defined(RTS_SUPPORTS_THREADS)
stopTaskManager();
#endif
}
......@@ -2022,7 +2086,7 @@ waitThread(StgTSO *tso, /*out*/StgClosure **ret)
m->ret = ret;
m->stat = NoStatus;
#if defined(RTS_SUPPORTS_THREADS)
initCondVar(&m->wakeup);
initCondition(&m->wakeup);
#endif
m->link = main_threads;
......@@ -2033,7 +2097,7 @@ waitThread(StgTSO *tso, /*out*/StgClosure **ret)
#ifdef SMP
do {
waitCondVar(&m->wakeup, &sched_mutex);
waitCondition(&m->wakeup, &sched_mutex);
} while (m->stat == NoStatus);
#elif defined(GRAN)
/* GranSim specific init */
......@@ -2043,6 +2107,7 @@ waitThread(StgTSO *tso, /*out*/StgClosure **ret)
schedule();
#else
RELEASE_LOCK(&sched_mutex);
schedule();
ASSERT(m->stat != NoStatus);
#endif
......@@ -2050,7 +2115,7 @@ waitThread(StgTSO *tso, /*out*/StgClosure **ret)
stat = m->stat;
#if defined(RTS_SUPPORTS_THREADS)
closeCondVar(&m->wakeup);
closeCondition(&m->wakeup);
#endif
IF_DEBUG(scheduler, fprintf(stderr, "== scheduler: main thread (%d) finished\n",
......@@ -3589,7 +3654,6 @@ sched_belch(char *s, ...)
//* sched_mutex:: @cindex\s-+sched_mutex
//* schedule:: @cindex\s-+schedule
//* take_off_run_queue:: @cindex\s-+take_off_run_queue
//* task_ids:: @cindex\s-+task_ids
//* term_mutex:: @cindex\s-+term_mutex
//* thread_ready_cond:: @cindex\s-+thread_ready_cond
//@end index
/* -----------------------------------------------------------------------------
* $Id: Schedule.h,v 1.25 2001/11/22 14:25:12 simonmar Exp $
* $Id: Schedule.h,v 1.26 2002/02/04 20:40:37 sof Exp $
*
* (c) The GHC Team 1998-1999
*
......@@ -7,6 +7,9 @@
* (RTS internal scheduler interface)
*
* -------------------------------------------------------------------------*/
#ifndef __SCHEDULE_H__
#define __SCHEDULE_H__
#include "OSThreads.h"
//@menu
//* Scheduler Functions::
......@@ -20,17 +23,13 @@
//@cindex initScheduler
//@cindex exitScheduler
//@cindex startTasks
/* initScheduler(), exitScheduler(), startTasks()
*
* Called from STG : no
* Locks assumed : none
*/
void initScheduler( void );
void exitScheduler( void );
#ifdef SMP
void startTasks( void );
#endif
extern void initScheduler ( void );
extern void exitScheduler ( void );
//@cindex awakenBlockedQueue
/* awakenBlockedQueue()
......@@ -157,31 +156,13 @@ extern StgTSO *sleeping_queue;
/* Linked list of all threads. */
extern StgTSO *all_threads;
#ifdef SMP
//@cindex sched_mutex
//@cindex thread_ready_cond
//@cindex gc_pending_cond
extern pthread_mutex_t sched_mutex;
extern pthread_cond_t thread_ready_cond;
extern pthread_cond_t gc_pending_cond;
#endif
//@cindex task_info
#ifdef SMP
typedef struct {
pthread_t id;
double elapsedtimestart;
double mut_time;
double mut_etime;
double gc_time;
double gc_etime;
} task_info;
extern task_info *task_ids;
#if defined(RTS_SUPPORTS_THREADS)
extern Mutex sched_mutex;
extern Condition thread_ready_cond;
extern Condition gc_pending_cond;
#endif
/* Needed by Hugs.
*/
/* Called by shutdown_handler(). */
void interruptStgRts ( void );
void raiseAsync(StgTSO *tso, StgClosure *exception);
......@@ -268,7 +249,7 @@ void print_bqe (StgBlockingQueueElement *bqe);
#ifdef SMP
#define THREAD_RUNNABLE() \
if (free_capabilities != NULL) { \
pthread_cond_signal(&thread_ready_cond); \
signalCondition(&thread_ready_cond); \
} \
context_switch = 1;
#else
......@@ -280,16 +261,16 @@ void print_bqe (StgBlockingQueueElement *bqe);
*/
#define EMPTY_RUN_QUEUE() (run_queue_hd == END_TSO_QUEUE)
#endif /* __SCHEDULE_H__ */
//@node Index, , Some convenient macros
//@subsection Index
//@index