Changeset 97e3296

Timestamp:

Aug 17, 2017, 3:42:16 PM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

aaron-thesis, arm-eh, cleanup-dtors, deferred_resn, demangler, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, resolv-new, with_gc

Children:

6ac5223

Parents:

f710aca

Message:

First working implementation of external scheduling... Still lots of testing to do

Location:

src

Files:

• Concurrency/Keywords.cc (modified) (7 diffs)
• libcfa/concurrency/invoke.h (modified) (2 diffs)
• libcfa/concurrency/kernel.c (modified) (2 diffs)
• libcfa/concurrency/monitor (modified) (3 diffs)
• libcfa/concurrency/monitor.c (modified) (19 diffs)
• tests/sched-ext.c (added)

src/Concurrency/Keywords.cc

@@ -200 +200 @@
                 std::list<DeclarationWithType*> findMutexArgs( FunctionDecl* );
                 void validate( DeclarationWithType * );
-                void addStatments( CompoundStmt *, const std::list<DeclarationWithType * > &);
+                void addStatments( FunctionDecl* func, CompoundStmt *, const std::list<DeclarationWithType * > &);
 
                 static void implement( std::list< Declaration * > & translationUnit ) {
@@ -210 +210 @@
                 StructDecl* monitor_decl = nullptr;
                 StructDecl* guard_decl = nullptr;
+
+                static std::unique_ptr< Type > generic_func;
         };
+
+        std::unique_ptr< Type > MutexKeyword::generic_func = std::unique_ptr< Type >(
+                new FunctionType(
+                        noQualifiers,
+                        true
+                )
+        );
 
         //-----------------------------------------------------------------------------
@@ -394 +403 @@
         // Mutex keyword implementation
         //=============================================================================================
+
         void MutexKeyword::visit(FunctionDecl* decl) {
                 Visitor::visit(decl);
@@ -410 +420 @@
                 if( !guard_decl ) throw SemanticError( "mutex keyword requires monitors to be in scope, add #include <monitor>", decl );
 
-                addStatments( body, mutexArgs );
+                addStatments( decl, body, mutexArgs );
         }
 
@@ -456 +466 @@
         }
 
-        void MutexKeyword::addStatments( CompoundStmt * body, const std::list<DeclarationWithType * > & args ) {
+        void MutexKeyword::addStatments( FunctionDecl* func, CompoundStmt * body, const std::list<DeclarationWithType * > & args ) {
                 ObjectDecl * monitors = new ObjectDecl(
                         "__monitors",
@@ -487 +497 @@
                 );
 
+                assert(generic_func);
+
                 //in reverse order :
-                // monitor_guard_t __guard = { __monitors, # };
+                // monitor_guard_t __guard = { __monitors, #, func };
                 body->push_front(
                         new DeclStmt( noLabels, new ObjectDecl(
@@ -502 +514 @@
                                         {
                                                 new SingleInit( new VariableExpr( monitors ) ),
-                                                new SingleInit( new ConstantExpr( Constant::from_ulong( args.size() ) ) )
+                                                new SingleInit( new ConstantExpr( Constant::from_ulong( args.size() ) ) ),
+                                                new SingleInit( new CastExpr( new VariableExpr( func ), generic_func->clone() ) )
                                         },
                                         noDesignators,

src/libcfa/concurrency/invoke.h

@@ -87 +87 @@
             struct __condition_stack_t signal_stack;  // stack of conditions to run next once we exit the monitor
             unsigned int recursion;                   // monitor routines can be called recursively, we need to keep track of that
-      };
+
+            struct __acceptable_t * acceptables;      // list of acceptable functions, null if any
+            unsigned short acceptable_count;          // number of acceptable functions
+            short accepted_index;                     // the index of the accepted function, -1 if none
+            void (*pre_accept)(void);                 // function to run before an accept
+       };
 
       struct thread_desc {
@@ -95 +100 @@
             struct monitor_desc ** current_monitors;  // currently held monitors
             unsigned short current_monitor_count;     // number of currently held monitors
-      };
+     };
 
 #endif //_INVOKE_H_

src/libcfa/concurrency/kernel.c

@@ -366 +366 @@
 
 void BlockInternal( thread_desc * thrd ) {
+        assert(thrd);
         disable_interrupts();
         assert( thrd->cor.state != Halted );
@@ -379 +380 @@
 
 void BlockInternal( spinlock * lock, thread_desc * thrd ) {
+        assert(thrd);
         disable_interrupts();
         this_processor->finish.action_code = Release_Schedule;

src/libcfa/concurrency/monitor

@@ -23 +23 @@
 
 static inline void ?{}(monitor_desc * this) {
+        (&this->lock){};
         this->owner = NULL;
+        (&this->entry_queue){};
+        (&this->signal_stack){};
         this->recursion = 0;
+        this->acceptables = NULL;
+        this->acceptable_count = 0;
+        this->accepted_index = -1;
+        this->pre_accept = 0;
 }
 
@@ -38 +45 @@
 }
 
-void ?{}( monitor_guard_t * this, monitor_desc ** m, int count );
+void ?{}( monitor_guard_t * this, monitor_desc ** m, int count, void (*func)() );
 void ^?{}( monitor_guard_t * this );
 
@@ -89 +96 @@
 uintptr_t front( condition * this );
 
+//-----------------------------------------------------------------------------
+// External scheduling
+
+typedef void (*void_fptr_t)(void);
+
 struct __acceptable_t {
-        void (*func)(void);
+        void_fptr_t func;
         unsigned short count;
-        monitor_desc * monitors[1];
+        monitor_desc ** monitors;
+        bool run_preaccept;
 };
 
-void __accept_internal( unsigned short count, __acceptable_t * acceptables, void (*func)(void) );
+int __accept_internal( unsigned short count, __acceptable_t * acceptables );
 
 // Local Variables: //

src/libcfa/concurrency/monitor.c

@@ -25 +25 @@
 static inline void set_owner( monitor_desc * this, thread_desc * owner );
 static inline thread_desc * next_thread( monitor_desc * this );
+static inline int is_accepted( thread_desc * owner, monitor_desc * this, monitor_desc ** group, int group_cnt, void (*func)() );
 
 static inline void lock_all( spinlock ** locks, unsigned short count );
@@ -34 +35 @@
 static inline void restore_recursion( monitor_desc ** ctx, unsigned int * /*in */ recursions, unsigned short count );
 
+static inline void init     ( int count, monitor_desc ** monitors, __condition_node_t * waiter, __condition_criterion_t * criteria );
+static inline void init_push( int count, monitor_desc ** monitors, __condition_node_t * waiter, __condition_criterion_t * criteria );
+
 static inline thread_desc * check_condition( __condition_criterion_t * );
 static inline void brand_condition( condition * );
 static inline unsigned short insert_unique( thread_desc ** thrds, unsigned short end, thread_desc * val );
 
+static inline thread_desc * search_entry_queue( __acceptable_t * acceptables, int acc_count, monitor_desc ** monitors, int count );
+
+//-----------------------------------------------------------------------------
+// Useful defines
+#define wait_ctx(thrd, user_info)                               /* Create the necessary information to use the signaller stack       */ \
+        __condition_node_t waiter = { thrd, count, user_info };   /* Create the node specific to this wait operation                   */ \
+        __condition_criterion_t criteria[count];                  /* Create the creteria this wait operation needs to wake up          */ \
+        init( count, monitors, &waiter, criteria );               /* Link everything together                                          */ \
+
+#define wait_ctx_primed(thrd, user_info)                        /* Create the necessary information to use the signaller stack       */ \
+        __condition_node_t waiter = { thrd, count, user_info };   /* Create the node specific to this wait operation                   */ \
+        __condition_criterion_t criteria[count];                  /* Create the creteria this wait operation needs to wake up          */ \
+        init_push( count, monitors, &waiter, criteria );          /* Link everything together and push it to the AS-Stack              */ \
+
+#define monitor_ctx( mons, cnt )              /* Define that create the necessary struct for internal/external scheduling operations */ \
+        monitor_desc ** monitors = mons;        /* Save the targeted monitors                                                          */ \
+        unsigned short count = cnt;             /* Save the count to a local variable                                                  */ \
+        unsigned int recursions[ count ];       /* Save the current recursion levels to restore them later                             */ \
+        spinlock *   locks     [ count ];       /* We need to pass-in an array of locks to BlockInternal                               */ \
+
 //-----------------------------------------------------------------------------
 // Enter/Leave routines
@@ -43 +67 @@
 
 extern "C" {
-        void __enter_monitor_desc( monitor_desc * this ) {
+        // Enter single monitor
+        static void __enter_monitor_desc( monitor_desc * this, monitor_desc ** group, int group_cnt, void (*func)() ) {
+                // Lock the monitor spinlock, lock_yield to reduce contention
                 lock_yield( &this->lock DEBUG_CTX2 );
                 thread_desc * thrd = this_thread;
 
-                // LIB_DEBUG_PRINT_SAFE("%p Entering %p (o: %p, r: %i)\n", thrd, this, this->owner, this->recursion);
-
+                this->accepted_index = -1;
                 if( !this->owner ) {
-                        //No one has the monitor, just take it
+                        // No one has the monitor, just take it
                         set_owner( this, thrd );
                 }
                 else if( this->owner == thrd) {
-                        //We already have the monitor, just not how many times we took it
+                        // We already have the monitor, just not how many times we took it
                         verify( this->recursion > 0 );
                         this->recursion += 1;
                 }
+                else if( (this->accepted_index = is_accepted( thrd, this, group, group_cnt, func)) >= 0 ) {
+                        // Some one was waiting for us, enter
+                        set_owner( this, thrd );
+                }
                 else {
-                        //Some one else has the monitor, wait in line for it
+                        // Some one else has the monitor, wait in line for it
                         append( &this->entry_queue, thrd );
-                        // LIB_DEBUG_PRINT_SAFE("%p Blocking on entry\n", thrd);
                         BlockInternal( &this->lock );
 
-                        //BlockInternal will unlock spinlock, no need to unlock ourselves
+                        // BlockInternal will unlock spinlock, no need to unlock ourselves
                         return;
                 }
 
+                // Release the lock and leave
                 unlock( &this->lock );
                 return;
         }
 
-        // leave pseudo code :
-        //      TODO
+        // Leave single monitor
         void __leave_monitor_desc( monitor_desc * this ) {
+                // Lock the monitor spinlock, lock_yield to reduce contention
                 lock_yield( &this->lock DEBUG_CTX2 );
 
-                // LIB_DEBUG_PRINT_SAFE("%p Leaving %p (o: %p, r: %i). ", this_thread, this, this->owner, this->recursion);
                 verifyf( this_thread == this->owner, "Expected owner to be %p, got %p (r: %i)", this_thread, this->owner, this->recursion );
 
-                //Leaving a recursion level, decrement the counter
+                // Leaving a recursion level, decrement the counter
                 this->recursion -= 1;
 
-                //If we haven't left the last level of recursion
-                //it means we don't need to do anything
+                // If we haven't left the last level of recursion
+                // it means we don't need to do anything
                 if( this->recursion != 0) {
                         unlock( &this->lock );
@@ -90 +118 @@
                 }
 
+                // Get the next thread, will be null on low contention monitor
                 thread_desc * new_owner = next_thread( this );
 
-                //We can now let other threads in safely
+                // We can now let other threads in safely
                 unlock( &this->lock );
-
-                // LIB_DEBUG_PRINT_SAFE("Next owner is %p\n", new_owner);
 
                 //We need to wake-up the thread
@@ -101 +128 @@
         }
 
+        // Leave the thread monitor
+        // last routine called by a thread.
+        // Should never return
         void __leave_thread_monitor( thread_desc * thrd ) {
                 monitor_desc * this = &thrd->mon;
+
+                // Lock the monitor now
                 lock_yield( &this->lock DEBUG_CTX2 );
 
@@ -111 +143 @@
                 verifyf( thrd == this->owner, "Expected owner to be %p, got %p (r: %i)", thrd, this->owner, this->recursion );
 
-                //Leaving a recursion level, decrement the counter
+                // Leaving a recursion level, decrement the counter
                 this->recursion -= 1;
 
-                //If we haven't left the last level of recursion
-                //it means we don't need to do anything
-                if( this->recursion != 0) {
-                        unlock( &this->lock );
-                        return;
-                }
-
+                // If we haven't left the last level of recursion
+                // it must mean there is an error
+                if( this->recursion != 0) { abortf("Thread internal monitor has unbalanced recursion"); }
+
+                // Fetch the next thread, can be null
                 thread_desc * new_owner = next_thread( this );
 
+                // Leave the thread, this will unlock the spinlock
+                // Use leave thread instead of BlockInternal which is
+                // specialized for this case and supports null new_owner
                 LeaveThread( &this->lock, new_owner );
-        }
-}
-
-static inline void enter(monitor_desc ** monitors, int count) {
+
+                // Control flow should never reach here!
+        }
+}
+
+// Enter multiple monitor
+// relies on the monitor array being sorted
+static inline void enter(monitor_desc ** monitors, int count, void (*func)() ) {
         for(int i = 0; i < count; i++) {
-                __enter_monitor_desc( monitors[i] );
-        }
-}
-
+                __enter_monitor_desc( monitors[i], monitors, count, func );
+        }
+
+        int acc_idx = monitors[0]->accepted_index;
+        if( acc_idx >= 0 && monitors[0]->acceptables[ acc_idx ].run_preaccept ) {
+                assert( monitors[0]->pre_accept );
+                monitors[0]->pre_accept();
+        }
+}
+
+// Leave multiple monitor
+// relies on the monitor array being sorted
 static inline void leave(monitor_desc ** monitors, int count) {
         for(int i = count - 1; i >= 0; i--) {
@@ -139 +184 @@
 }
 
-void ?{}( monitor_guard_t * this, monitor_desc ** m, int count ) {
+// Ctor for monitor guard
+// Sorts monitors before entering
+void ?{}( monitor_guard_t * this, monitor_desc ** m, int count, void (*func)() ) {
+        // Store current array
         this->m = m;
         this->count = count;
+
+        // Sort monitors based on address -> TODO use a sort specialized for small numbers
         qsort(this->m, count);
-        enter( this->m, this->count );
-
+
+        // Enter the monitors in order
+        enter( this->m, this->count, func );
+
+        // Save previous thread context
         this->prev_mntrs = this_thread->current_monitors;
         this->prev_count = this_thread->current_monitor_count;
 
+        // Update thread context (needed for conditions)
         this_thread->current_monitors      = m;
         this_thread->current_monitor_count = count;
 }
 
+// Dtor for monitor guard
 void ^?{}( monitor_guard_t * this ) {
+        // Leave the monitors in order
         leave( this->m, this->count );
 
+        // Restore thread context
         this_thread->current_monitors      = this->prev_mntrs;
         this_thread->current_monitor_count = this->prev_count;
 }
+
+//-----------------------------------------------------------------------------
+// Internal scheduling types
 
 void ?{}(__condition_node_t * this, thread_desc * waiting_thread, unsigned short count, uintptr_t user_info ) {
@@ -183 +243 @@
 // Internal scheduling
 void wait( condition * this, uintptr_t user_info = 0 ) {
-        // LIB_DEBUG_PRINT_SAFE("Waiting\n");
-
         brand_condition( this );
 
-        //Check that everything is as expected
+        // Check that everything is as expected
         assertf( this->monitors != NULL, "Waiting with no monitors (%p)", this->monitors );
         verifyf( this->monitor_count != 0, "Waiting with 0 monitors (%i)", this->monitor_count );
         verifyf( this->monitor_count < 32u, "Excessive monitor count (%i)", this->monitor_count );
 
-        unsigned short count = this->monitor_count;
-        unsigned int recursions[ count ];               //Save the current recursion levels to restore them later
-        spinlock *   locks     [ count ];               //We need to pass-in an array of locks to BlockInternal
-
-        // LIB_DEBUG_PRINT_SAFE("count %i\n", count);
-
-        __condition_node_t waiter = { (thread_desc*)this_thread, count, user_info };
-
-        __condition_criterion_t criteria[count];
-        for(int i = 0; i < count; i++) {
-                (&criteria[i]){ this->monitors[i], &waiter };
-                // LIB_DEBUG_PRINT_SAFE( "Criterion %p\n", &criteria[i] );
-        }
-
-        waiter.criteria = criteria;
+        // Create storage for monitor context
+        monitor_ctx( this->monitors, this->monitor_count );
+
+        // Create the node specific to this wait operation
+        wait_ctx( this_thread, user_info );
+
+        // Append the current wait operation to the ones already queued on the condition
+        // We don't need locks for that since conditions must always be waited on inside monitor mutual exclusion
         append( &this->blocked, &waiter );
 
-        lock_all( this->monitors, locks, count );
-        save_recursion( this->monitors, recursions, count );
-        //DON'T unlock, ask the kernel to do it
-
-        //Find the next thread(s) to run
+        // Lock all monitors (aggregates the lock them as well)
+        lock_all( monitors, locks, count );
+
+        // DON'T unlock, ask the kernel to do it
+
+        // Save monitor state
+        save_recursion( monitors, recursions, count );
+
+        // Find the next thread(s) to run
         unsigned short thread_count = 0;
         thread_desc * threads[ count ];
@@ -220 +275 @@
         }
 
+        // Remove any duplicate threads
         for( int i = 0; i < count; i++) {
-                thread_desc * new_owner = next_thread( this->monitors[i] );
+                thread_desc * new_owner = next_thread( monitors[i] );
                 thread_count = insert_unique( threads, thread_count, new_owner );
         }
-
-        // LIB_DEBUG_PRINT_SAFE("Will unblock: ");
-        for(int i = 0; i < thread_count; i++) {
-                // LIB_DEBUG_PRINT_SAFE("%p ", threads[i]);
-        }
-        // LIB_DEBUG_PRINT_SAFE("\n");
 
         // Everything is ready to go to sleep
@@ -235 +285 @@
 
 
-        //WE WOKE UP
-
-
-        //We are back, restore the owners and recursions
+        // WE WOKE UP
+
+
+        // We are back, restore the owners and recursions
         lock_all( locks, count );
-        restore_recursion( this->monitors, recursions, count );
+        restore_recursion( monitors, recursions, count );
         unlock_all( locks, count );
 }
 
 bool signal( condition * this ) {
-        if( is_empty( this ) ) {
-                // LIB_DEBUG_PRINT_SAFE("Nothing to signal\n");
-                return false;
-        }
+        if( is_empty( this ) ) { return false; }
 
         //Check that everything is as expected
         verify( this->monitors );
         verify( this->monitor_count != 0 );
-
-        unsigned short count = this->monitor_count;
 
         //Some more checking in debug
@@ -261 +306 @@
                 if ( this->monitor_count != this_thrd->current_monitor_count ) {
                         abortf( "Signal on condition %p made with different number of monitor(s), expected %i got %i", this, this->monitor_count, this_thrd->current_monitor_count );
-                } // if
+                }
 
                 for(int i = 0; i < this->monitor_count; i++) {
                         if ( this->monitors[i] != this_thrd->current_monitors[i] ) {
                                 abortf( "Signal on condition %p made with different monitor, expected %p got %i", this, this->monitors[i], this_thrd->current_monitors[i] );
-                        } // if
+                        }
                 }
         );
 
-        //Lock all the monitors
+        unsigned short count = this->monitor_count;
+
+        // Lock all monitors
         lock_all( this->monitors, NULL, count );
-        // LIB_DEBUG_PRINT_SAFE("Signalling");
 
         //Pop the head of the waiting queue
@@ -280 +326 @@
         for(int i = 0; i < count; i++) {
                 __condition_criterion_t * crit = &node->criteria[i];
-                // LIB_DEBUG_PRINT_SAFE(" %p", crit->target);
                 assert( !crit->ready );
                 push( &crit->target->signal_stack, crit );
         }
 
-        // LIB_DEBUG_PRINT_SAFE("\n");
-
         //Release
         unlock_all( this->monitors, count );
@@ -294 +337 @@
 
 bool signal_block( condition * this ) {
-        if( !this->blocked.head ) {
-                LIB_DEBUG_PRINT_SAFE("Nothing to signal\n");
-                return false;
-        }
+        if( !this->blocked.head ) { return false; }
 
         //Check that everything is as expected
@@ -303 +343 @@
         verifyf( this->monitor_count != 0, "Waiting with 0 monitors (%i)", this->monitor_count );
 
-        unsigned short count = this->monitor_count;
-        unsigned int recursions[ count ];               //Save the current recursion levels to restore them later
-        spinlock *   locks     [ count ];               //We need to pass-in an array of locks to BlockInternal
-
-        lock_all( this->monitors, locks, count );
-
-        //create creteria
-        __condition_node_t waiter = { (thread_desc*)this_thread, count, 0 };
-
-        __condition_criterion_t criteria[count];
-        for(int i = 0; i < count; i++) {
-                (&criteria[i]){ this->monitors[i], &waiter };
-                // LIB_DEBUG_PRINT_SAFE( "Criterion %p\n", &criteria[i] );
-                push( &criteria[i].target->signal_stack, &criteria[i] );
-        }
-
-        waiter.criteria = criteria;
+        // Create storage for monitor context
+        monitor_ctx( this->monitors, this->monitor_count );
+
+        // Lock all monitors (aggregates the locks them as well)
+        lock_all( monitors, locks, count );
+
+        // Create the node specific to this wait operation
+        wait_ctx_primed( this_thread, 0 )
 
         //save contexts
-        save_recursion( this->monitors, recursions, count );
+        save_recursion( monitors, recursions, count );
 
         //Find the thread to run
         thread_desc * signallee = pop_head( &this->blocked )->waiting_thread;
         for(int i = 0; i < count; i++) {
-                set_owner( this->monitors[i], signallee );
-        }
-
-        LIB_DEBUG_PRINT_SAFE( "Waiting on signal block\n" );
+                set_owner( monitors[i], signallee );
+        }
 
         //Everything is ready to go to sleep
@@ -336 +365 @@
 
 
-
-
-        LIB_DEBUG_PRINT_SAFE( "Back from signal block\n" );
+        // WE WOKE UP
+
 
         //We are back, restore the owners and recursions
         lock_all( locks, count );
-        restore_recursion( this->monitors, recursions, count );
+        restore_recursion( monitors, recursions, count );
         unlock_all( locks, count );
 
@@ -348 +376 @@
 }
 
+// Access the user_info of the thread waiting at the front of the queue
 uintptr_t front( condition * this ) {
         verifyf( !is_empty(this),
@@ -358 +387 @@
 //-----------------------------------------------------------------------------
 // Internal scheduling
-void __accept_internal( unsigned short count, __acceptable_t * acceptables, void (*func)(void) ) {
-        // thread_desc * this = this_thread;
-
-        // unsigned short count = this->current_monitor_count;
-        // unsigned int recursions[ count ];            //Save the current recursion levels to restore them later
-        // spinlock *   locks     [ count ];            //We need to pass-in an array of locks to BlockInternal
-
-        // lock_all( this->current_monitors, locks, count );
-
-
-
-
-
-        // // // Everything is ready to go to sleep
-        // // BlockInternal( locks, count, threads, thread_count );
-
-
-        // //WE WOKE UP
-
-
-        // //We are back, restore the owners and recursions
-        // lock_all( locks, count );
-        // restore_recursion( this->monitors, recursions, count );
-        // unlock_all( locks, count );
+int __accept_internal( unsigned short acc_count, __acceptable_t * acceptables ) {
+        thread_desc * thrd = this_thread;
+
+        // Create storage for monitor context
+        monitor_ctx( acceptables->monitors, acceptables->count );
+
+        // Lock all monitors (aggregates the lock them as well)
+        lock_all( monitors, locks, count );
+
+        // Create the node specific to this wait operation
+        wait_ctx_primed( thrd, 0 );
+
+        // Check if the entry queue
+        thread_desc * next = search_entry_queue( acceptables, acc_count, monitors, count );
+
+        if( !next ) {
+                // Update acceptables on the current monitors
+                for(int i = 0; i < count; i++) {
+                        monitors[i]->acceptables = acceptables;
+                        monitors[i]->acceptable_count = acc_count;
+                }
+        }
+
+        save_recursion( monitors, recursions, count );
+
+        // Everything is ready to go to sleep
+        BlockInternal( locks, count, &next, next ? 1 : 0 );
+
+
+        //WE WOKE UP
+
+
+        //We are back, restore the owners and recursions
+        lock_all( locks, count );
+        restore_recursion( monitors, recursions, count );
+        int acc_idx = monitors[0]->accepted_index;
+        unlock_all( locks, count );
+
+        return acc_idx;
 }
 
@@ -415 +459 @@
 }
 
+static inline int is_accepted( thread_desc * owner, monitor_desc * this, monitor_desc ** group, int group_cnt, void (*func)() ) {
+        __acceptable_t* accs = this->acceptables; // Optim
+        int acc_cnt = this->acceptable_count;
+
+        // Check if there are any acceptable functions
+        if( !accs ) return -1;
+
+        // If this isn't the first monitor to test this, there is no reason to repeat the test.
+        if( this != group[0] ) return group[0]->accepted_index;
+
+        // For all acceptable functions check if this is the current function.
+        OUT_LOOP:
+        for( int i = 0; i < acc_cnt; i++ ) {
+                __acceptable_t * acc = &accs[i];
+
+                // if function matches, check the monitors
+                if( acc->func == func ) {
+
+                        // If the group count is different then it can't be a match
+                        if( acc->count != group_cnt ) return -1;
+
+                        // Check that all the monitors match
+                        for( int j = 0; j < group_cnt; j++ ) {
+                                // If not a match, check next function
+                                if( acc->monitors[j] != group[j] ) continue OUT_LOOP;
+                        }
+
+                        // It's a complete match, accept the call
+                        return i;
+                }
+        }
+
+        // No function matched
+        return -1;
+}
+
+static inline void init( int count, monitor_desc ** monitors, __condition_node_t * waiter, __condition_criterion_t * criteria ) {
+        for(int i = 0; i < count; i++) {
+                (&criteria[i]){ monitors[i], waiter };
+        }
+
+        waiter->criteria = criteria;
+}
+
+static inline void init_push( int count, monitor_desc ** monitors, __condition_node_t * waiter, __condition_criterion_t * criteria ) {
+        for(int i = 0; i < count; i++) {
+                (&criteria[i]){ monitors[i], waiter };
+                push( &criteria[i].target->signal_stack, &criteria[i] );
+        }
+
+        waiter->criteria = criteria;
+}
+
 static inline void lock_all( spinlock ** locks, unsigned short count ) {
         for( int i = 0; i < count; i++ ) {
@@ -505 +602 @@
 }
 
+static inline thread_desc * search_entry_queue( __acceptable_t * acceptables, int acc_count, monitor_desc ** monitors, int count ) {
+        return NULL;
+}
+
 void ?{}( __condition_blocked_queue_t * this ) {
         this->head = NULL;