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sync_object.h
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sync_object.h
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#ifndef SYNC_OBJECT_H
#define SYNC_OBJECT_H
#ifndef FIBER_TYPES_ONLY
#include <cassert>
#include "sched.h"
#endif
#include "llq_ctypes.h"
enum dispatch_method{
D_SINGLETHREAD,
D_CONCURRENT
};
struct fiber_sync_object{
struct llq_queue queue;
llq_word control;
#ifndef FIBER_TYPES_ONLY
enum {CONCURRENT = 0x100, UNUSED = 0xffffff, OWNER_START=0x1000000};
fiber_sync_object(word tag = 0){
init(tag);
}
void init(word tag = 0){
control = UNUSED;
// control = OWNER_START + worker::current().id;
//llq::spin_init(&control);
llq::queue_init(&queue, tag);
}
#ifdef FIBER_SINGLETHREADED
#define DISPMETH -1
#else
#define DISPMETH 1
#endif
dispatch_method begin_operation(){
llq::concurrent_ops::begin(&queue);
word OWNED_SELF = OWNER_START + worker::current().id;
#if DISPMETH == -1
return D_SINGLETHREAD;
#elif DISPMETH == 0
word ctrl = llq::load_relaxed(&control);
if (ctrl == OWNER_START + worker::current().id){
// owned by us
worker::current().stats.owned++;
}else if (ctrl == UNUSED && llq::cas(&control, UNUSED, OWNED_SELF)){
// unowned, we took it
}else{
ctrl = llq::load_relaxed(&control);
assert(ctrl & OWNER_START);
assert(ctrl != OWNED_SELF);
// owned by another worker, migrate
int other = ctrl & ~OWNER_START;
worker::current().migrate(other);
}
return D_SINGLETHREAD;
#elif DISPMETH == 1
worker::current().stats.conc++; return D_CONCURRENT;
#elif DISPMETH == 2
word ctrl = llq::load_relaxed(&control);
if (ctrl == OWNED_SELF){
// object is owned by current worker
say("LOCKS[%p] already owned\n", this);
worker::current().stats.owned++;
return D_SINGLETHREAD;
}else if (ctrl == UNUSED && llq::cas(&control, UNUSED, OWNED_SELF)){
// object is taken by current worker
say("LOCKS[%p]: taken\n", this);
return D_SINGLETHREAD;
}else{
if (ctrl & OWNER_START){
// object is owned by some other worker
int other = ctrl & ~OWNER_START;
say("LOCKS[%p]: Need, but owned by %d\n", this, other);
worker::current().migrate(other);
// control field may have changed while we migrated
word newctrl = llq::load_relaxed(&control);
assert(newctrl == ctrl || newctrl == CONCURRENT);
// in theory, we need only store if it's not already
// in state CONCURRENT. But it's faster not to branch.
llq::store_relaxed(&control, CONCURRENT);
say("LOCKS[%p]: Made concurrent\n", this);
}else{
say("LOCKS[%p]: concurrent\n", this);
}
worker::current().stats.conc++;
// object is shared
return D_CONCURRENT;
}
#endif
}
void end_operation(){
llq::concurrent_ops::end(&queue);
}
#endif
};
#ifndef FIBER_TYPES_ONLY
struct mutex{
fiber_sync_object sync;
enum { UNLOCKED, LOCKED };
template <class ops>
static void lock_impl(llq::queue* q){
using llq::word;
while (1){
word state = ops::get_state(q);
if (ops::tag(q, state) == LOCKED){
waiter<void> waiter;
if (ops::try_enqueue(q, &waiter, state, LOCKED)){
worker::current().sleep(waiter);
return;
}
}else{
assert(ops::isempty(q, state));
assert(ops::tag(q, state) == UNLOCKED);
if (ops::try_transition(q, state, LOCKED)){
return;
}
}
}
}
static void lock(fiber_sync_object& sync){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) lock_impl<single_thread_ops>(&sync.queue);
else lock_impl<concurrent_ops>(&sync.queue);
sync.end_operation();
}
void lock(){
lock(sync);
}
template <class ops>
static waiter<void>* unlock_getwaiter_impl(llq::queue* q){
using llq::word;
while (1){
word state = ops::get_state(q);
assert(ops::tag(q, state) == LOCKED);
if (ops::isempty(q, state)){
if (ops::try_transition(q, state, UNLOCKED)){
// No waiter
return 0;
}
}else{
llq::node* waiting;
if (ops::try_dequeue(q, &waiting, state, LOCKED)){
return static_cast<waiter<void>* >(waiting);
}
}
}
}
template <class ops>
static void unlock_impl(llq::queue* q){
waiter<void>* w = unlock_getwaiter_impl<ops>(q);
if (w){
// FIXME: maybe wake rather than sched?
worker::current().push_runqueue(w);
}
}
static void unlock(fiber_sync_object& sync){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) unlock_impl<single_thread_ops>(&sync.queue);
else unlock_impl<concurrent_ops>(&sync.queue);
sync.end_operation();
}
void unlock(){
unlock(sync);
}
static waiter<void>* unlock_getwaiter(fiber_sync_object& sync){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) return unlock_getwaiter_impl<single_thread_ops>(&sync.queue);
else return unlock_getwaiter_impl<concurrent_ops>(&sync.queue);
sync.end_operation();
}
waiter<void>* unlock_getwaiter(){
return unlock_getwaiter(sync);
}
};
struct condition_var{
fiber_sync_object sync;
template <class ops>
static void wait_impl(llq::queue* q, fiber_sync_object& mtx){
using llq::word;
waiter<void> w;
while (1){
word state = ops::get_state(q);
if (ops::try_enqueue(q, &w, state, 0)){
break;
}
}
waiter<void>* lockwaiter = mutex::unlock_getwaiter(mtx);
if (lockwaiter){
w.invoke(lockwaiter);
}else{
worker::current().sleep(w);
}
mutex::lock(mtx);
}
static void wait(fiber_sync_object& sync, fiber_sync_object& mtx){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) wait_impl<single_thread_ops>(&sync.queue, mtx);
else wait_impl<concurrent_ops>(&sync.queue, mtx);
sync.end_operation();
}
void wait(mutex* mtx){
wait(sync, mtx->sync);
}
template <class ops>
static void signal_impl(llq::queue* q, bool wake_all){
using llq::word;
while (1){
word state = ops::get_state(q);
llq::node* waiting;
if (ops::isempty(q, state)){
// Nobody listening, signal went nowhere
break;
}else if (ops::try_dequeue(q, &waiting, state, 0)){
// FIXME: wake vs. sched
// FIXME: this could be faster: push to mutexq instead of runq
worker::current().push_runqueue(static_cast<waiter<void>* >(waiting));
if (!wake_all) break;
}
}
}
static void signal(fiber_sync_object& sync){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) signal_impl<single_thread_ops>(&sync.queue, false);
else signal_impl<single_thread_ops>(&sync.queue, false);
sync.end_operation();
}
void signal(){
signal(sync);
}
static void broadcast(fiber_sync_object& sync){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) signal_impl<single_thread_ops>(&sync.queue, true);
else signal_impl<single_thread_ops>(&sync.queue, true);
sync.end_operation();
}
void broadcast(){
broadcast(sync);
}
};
template <class T>
struct blocking_channel{
fiber_sync_object sync;
struct writer_wait : public waiter<void>{
T data;
};
enum { WAIT_WRITE, WAIT_READ };
template <class ops>
static void write_impl2(llq::queue* q, T data) NOINLINE{
printf("IN2\n");
using llq::word;
while (1){
word state = ops::get_state(q);
if (ops::isempty(q, state) || ops::tag(q, state) == WAIT_WRITE){
writer_wait w;
w.data = data;
if (ops::try_enqueue(q, &w, state, WAIT_WRITE)){
worker::current().sleep(w);
return;
}
}else{
node* peer_;
if (ops::try_dequeue(q, &peer_, state, 0)){
waiter<void> self;
// FIXME read_func should happen earlier, maybe?
worker::current().push_runqueue(&self);
self.invoke(static_cast<waiter<T>* >(peer_), data);
return;
}
}
}
}
template <class ops>
static void write_impl(llq::queue* q, T data){
using llq::word;
/*while (1)*/{
word state = ops::get_state(q);
if (ops::isempty(q, state) || ops::tag(q, state) == WAIT_WRITE){
writer_wait w;
w.data = data;
if (ops::try_enqueue(q, &w, state, WAIT_WRITE)){
worker::current().sleep(w);
return;
}
}else{
node* peer_;
if (ops::try_dequeue(q, &peer_, state, 0)){
waiter<void> self;
// FIXME read_func should happen earlier, maybe?
worker::current().push_runqueue(&self);
self.invoke(static_cast<waiter<T>* >(peer_), data);
return;
}
}
}
write_impl2<ops>(q, data);
}
template <class ops>
static T read_impl(llq::queue* q){
using llq::word;
while (1){
word state = ops::get_state(q);
if (ops::isempty(q, state) || ops::tag(q, state) == WAIT_READ){
waiter<T> self;
if (ops::try_enqueue(q, &self, state, WAIT_READ)){
waiter<void>* waiting = worker::current().pop_runqueue();
return self.invoke(waiting);
}
}else{
llq::node* peer_;
if (ops::try_dequeue(q, &peer_, state, 0)){
// We must read the data before we add the writer to the runqueue
// in case the writer gets work-stolen and the data deallocated
writer_wait* peer = static_cast<writer_wait*>(peer_);
T data = peer->data;
// FIXME barriers? #LoadStore ?
// FORKPOINT
worker::current().push_runqueue(peer);
return data;
}
}
}
}
void write(T data){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) write_impl<single_thread_ops>(&sync.queue, data);
else write_impl<concurrent_ops>(&sync.queue, data);
sync.end_operation();
}
T read(){
dispatch_method meth = sync.begin_operation();
T result;
if (meth == D_SINGLETHREAD) result = read_impl<single_thread_ops>(&sync.queue);
else result = read_impl<concurrent_ops>(&sync.queue);
sync.end_operation();
return result;
}
};
template <class T>
struct blocker{
fiber_sync_object sync;
struct blocker_wait : public waiter<void>{
T data;
};
enum { WAIT_BLOCK, WAIT_ACCEPT };
template <class ops>
static void block_impl(llq::queue* q, T data){
using llq::word;
blocker_wait w;
w.data = data;
while (1){
word state = ops::get_state(q);
if (ops::isempty(q, state)){
if (ops::try_enqueue(q, &w, state, WAIT_BLOCK)){
worker::current().sleep(w);
return;
}
}else{
assert(ops::tag(q, state) == WAIT_ACCEPT);
node* peer_;
if (ops::try_dequeue(q, &peer_, state, 0)){
waiter<blocker_wait*>* peer = static_cast<waiter<blocker_wait*>* >(peer_);
w.invoke(peer, &w);
return;
}
}
}
}
template <class ops>
static blocker_wait* accept_impl(llq::queue* q){
using llq::word;
while (1){
word state = ops::get_state(q);
if (ops::isempty(q, state)){
waiter<blocker_wait*> self;
say("Accept is waiting: %p\n", &self);
if (ops::try_enqueue(q, &self, state, WAIT_ACCEPT)){
return worker::current().sleep(self);
}
}else{
assert(ops::tag(q, state) == WAIT_BLOCK);
llq::node* peer_;
if (ops::try_dequeue(q, &peer_, state, 0)){
return static_cast<blocker_wait*>(peer_);
}
}
}
}
void block(T data){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) block_impl<single_thread_ops>(&sync.queue, data);
else block_impl<concurrent_ops>(&sync.queue, data);
sync.end_operation();
}
blocker_wait* accept(){
dispatch_method meth = sync.begin_operation();
blocker_wait* result;
if (meth == D_SINGLETHREAD) result = accept_impl<single_thread_ops>(&sync.queue);
else result = accept_impl<concurrent_ops>(&sync.queue);
sync.end_operation();
return result;
}
};
#if 0
template <class T>
struct actor{
fiber_sync_object sync;
void send(T data){
dispatch_method meth = sync.begin_operation();
if (meth == D_SINGLETHREAD) send_impl<single_thread_ops>(data);
else send_impl<concurrent_ops>(data);
sync.end_operation();
}
T receive(){
dispatch_method meth = sync.begin_operation();
T result;
if (meth == D_SINGLETHREAD) result = receive_impl<single_thread_ops>();
else result = receive_impl<concurrent_ops>();
sync.end_operation();
return result;
}
enum { ACTOR_RECEIVE, ACTOR_RUN };
struct wdata{
func_t** loc;
T data;
};
typedef SWAPSTACK resume_context (*actor_direct_send)(wdata*);
template <class ops>
static void send_impl(llq::queue* q, T data){
using llq::word;
while (1){
word state = ops::get_state(q);
if (ops::tag(q, state) == ACTOR_RECEIVE){
waiter* actor;
waiter selfsleep;
if (ops::try_dequeue(q, &actor, state, ACTOR_RUN)){
worker::current.push_runqueue(&self);
wdata msg = {&self.func, data};
actor_direct_send actorsend = (actor_direct_send)actor->read_func();
post_context_switch(actorsend(&msg));
}
}else{
if (ops::try_enqueue(q, &w,
}
}
}
};
#endif
#endif // FIBER_TYPES_ONLY
#endif // header guard