Changeset 6b4cdd3 for src/libcfa/concurrency/kernel.c

Timestamp:

May 30, 2018, 5:57:35 PM (6 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, with_gc

Children:

ae32d96

Parents:

8cc7dd1

Message:

Added basic core quiescing

File:

• src/libcfa/concurrency/kernel.c (modified) (5 diffs)

src/libcfa/concurrency/kernel.c

@@ -143 +143 @@
         runner.proc = &this;
 
+        sem_init(&idleLock, 0, 0);
+
         start( &this );
 }
@@ -156 +158 @@
                 pthread_join( kernel_thread, NULL );
         }
+
+        sem_destroy(&idleLock);
 }
 
@@ -289 +293 @@
 // TODO : find some strategy to put cores to sleep after some time
 void spin(processor * this, unsigned int * spin_count) {
-        (*spin_count)++;
+        // (*spin_count)++;
+        halt(this);
 }
 
@@ -394 +399 @@
         with( *thrd->curr_cluster ) {
                 lock  ( ready_queue_lock __cfaabi_dbg_ctx2 );
+                bool was_empty = !(ready_queue != 0);
                 append( ready_queue, thrd );
                 unlock( ready_queue_lock );
+
+                if( was_empty ) {
+                        lock      (proc_list_lock __cfaabi_dbg_ctx2);
+                        if(idles) {
+                                wake(idles.head);
+                        }
+                        unlock    (proc_list_lock);
+                }
         }
 
@@ -639 +653 @@
 //=============================================================================================
 
-// void halt(processor * this) with( this ) {
-//      pthread_mutex_lock( &idle.lock );
-
-
-
-//      // SKULLDUGGERY: Even if spurious wake-up is a thing
-//      // spuriously waking up a kernel thread is not a big deal
-//      // if it is very rare.
-//      pthread_cond_wait( &idle.cond, &idle.lock);
-//      pthread_mutex_unlock( &idle.lock );
-// }
-
-// void wake(processor * this) with( this ) {
-//      pthread_mutex_lock  (&idle.lock);
-//      pthread_cond_signal (&idle.cond);
-//      pthread_mutex_unlock(&idle.lock);
-// }
+void halt(processor * this) with( *this ) {
+        with( *cltr ) {
+                lock      (proc_list_lock __cfaabi_dbg_ctx2);
+                remove    (procs, *this);
+                push_front(idles, *this);
+                unlock    (proc_list_lock);
+        }
+
+        __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
+
+        sem_wait(&idleLock);
+
+        __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
+
+        with( *cltr ) {
+                lock      (proc_list_lock __cfaabi_dbg_ctx2);
+                remove    (idles, *this);
+                push_front(procs, *this);
+                unlock    (proc_list_lock);
+        }
+}
+
+void wake(processor * this) {
+        __cfaabi_dbg_print_safe("Kernel : Waking up processor %p\n", this);
+        sem_post(&this->idleLock);
+}
 
 //=============================================================================================