Made task threads wait instead of sleep, so they can be woken up. This appears to give us much better parallel performance.

Also, commented out one more unsafe log and updated rust_kernel.cpp to compile under g++

src/rt/rust_task.cpp

@@ -105,7 +105,7 @@ rust_task::~rust_task()
 
     /* FIXME: tighten this up, there are some more
        assertions that hold at task-lifecycle events. */
-    // I(sched, ref_count == 0 ||
+    I(sched, ref_count == 0); // ||
     //   (ref_count == 1 && this == sched->root_task));
 
     del_stk(this, stk);
@@ -167,6 +167,7 @@ rust_task::start(uintptr_t spawnee_fn,
 
     yield_timer.reset_us(0);
     transition(&sched->newborn_tasks, &sched->running_tasks);
+    sched->lock.signal();
 }
 
 void
@@ -212,6 +213,8 @@ rust_task::kill() {
     if (NULL == supervisor && propagate_failure)
         sched->fail();
 
+    sched->lock.signal();
+
     LOG(this, task, "preparing to unwind task: 0x%" PRIxPTR, this);
     // run_on_resume(rust_unwind_glue);
 }
@@ -442,12 +445,15 @@ rust_task::wakeup(rust_cond *from) {
     if(_on_wakeup) {
         _on_wakeup->on_wakeup();
     }
+
+    sched->lock.signal();
 }
 
 void
 rust_task::die() {
     scoped_lock with(lock);
     transition(&sched->running_tasks, &sched->dead_tasks);
+    sched->lock.signal();
 }
 
 void