Merge branch 'laws-set-affinity' into 'master'

[LAWS] Set fiber affinity *before* dispatching it, not after

See merge request i4/manycore/emper!189

emper/strategies/laws/LawsDispatcher.cpp

@@ -53,11 +53,17 @@ void LawsDispatcher::dispatchLoop() {
 				}
 			}
 
-			// The fiber was marked das runnable. Run it now.
-			dispatch(fiber);
-			// Update the affinity if one was set.
+			// Update the affinity if one was set. Note that we do this
+			// before dispatching the fiber, as the fiber will change the
+			// affinity towards the current worker as soon as it starts
+			// executing, i.e. right now. Also, future code may delete the
+			// affinity buffer as part of the Fiber's run() method, so it
+			// may not longer be valid after dispatching it.
 			workeraffinity_t* const affinity = getAffinityBuffer(fiber);
 			if (affinity) *affinity = Runtime::getWorkerId();
+
+			// The fiber was marked das runnable. Run it now.
+			dispatch(fiber);
 		}
 
 		recycle(fiber);