jdk-sandbox: comparison src/hotspot/share/gc/shared/taskqueue.hpp

equal deleted inserted replaced

-:57aa80913140
+:0538a5cdb474
 #ifndef SHARE_VM_GC_SHARED_TASKQUEUE_HPP
 #define SHARE_VM_GC_SHARED_TASKQUEUE_HPP
 #include "memory/allocation.hpp"
+#include "memory/padded.hpp"
 #include "oops/oopsHierarchy.hpp"
 #include "utilities/ostream.hpp"
 #include "utilities/stack.hpp"
 // Simple TaskQueue stats that are collected by default in debug builds.
 // Apply fn to each element in the task queue.  The queue must not
 // be modified while iterating.
 template<typename Fn> void iterate(Fn fn);
 private:
+DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, 0);
 // Element array.
 volatile E* _elems;
+DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, sizeof(E*));
+// Queue owner local variables. Not to be accessed by other threads.
+static const uint InvalidQueueId = uint(-1);
+uint _last_stolen_queue_id; // The id of the queue we last stole from
+int _seed; // Current random seed used for selecting a random queue during stealing.
+DEFINE_PAD_MINUS_SIZE(2, DEFAULT_CACHE_LINE_SIZE, sizeof(uint) + sizeof(int));
+public:
+int next_random_queue_id();
+void set_last_stolen_queue_id(uint id)     { _last_stolen_queue_id = id; }
+uint last_stolen_queue_id() const          { return _last_stolen_queue_id; }
+bool is_last_stolen_queue_id_valid() const { return _last_stolen_queue_id != InvalidQueueId; }
+void invalidate_last_stolen_queue_id()     { _last_stolen_queue_id = InvalidQueueId; }
 };
 template<class E, MEMFLAGS F, unsigned int N>
-GenericTaskQueue<E, F, N>::GenericTaskQueue() {
+GenericTaskQueue<E, F, N>::GenericTaskQueue() : _last_stolen_queue_id(InvalidQueueId), _seed(17 /* random number */) {
 assert(sizeof(Age) == sizeof(size_t), "Depends on this.");
 }
 // OverflowTaskQueue is a TaskQueue that also includes an overflow stack for
 // elements that do not fit in the TaskQueue.
 private:
 overflow_t _overflow_stack;
 };
 class TaskQueueSetSuper {
-protected:
-static int randomParkAndMiller(int* seed0);
 public:
 // Returns "true" if some TaskQueue in the set contains a task.
 virtual bool peek() = 0;
 };
 private:
 uint _n;
 T** _queues;
-bool steal_best_of_2(uint queue_num, int* seed, E& t);
+bool steal_best_of_2(uint queue_num, E& t);
 public:
-GenericTaskQueueSet(int n);
+GenericTaskQueueSet(uint n);
 ~GenericTaskQueueSet();
 void register_queue(uint i, T* q);
 T* queue(uint n);
-// The thread with queue number "queue_num" (and whose random number seed is
+// Try to steal a task from some other queue than queue_num. It may perform several attempts at doing so.
-// at "seed") is trying to steal a task from some other queue.  (It may try
+// Returns if stealing succeeds, and sets "t" to the stolen task.
-// several queues, according to some configuration parameter.)  If some steal
+bool steal(uint queue_num, E& t);
-// succeeds, returns "true" and sets "t" to the stolen task, otherwise returns
-// false.
-bool steal(uint queue_num, int* seed, E& t);
 bool peek();
 uint size() const { return _n; }
 };

changeset 51292	0538a5cdb474
parent 50953	0fad17c646c9
child 52122	cb20bf10cfbd