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src/hotspot/share/gc/g1/g1ConcurrentRefine.hpp
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rev 47863 : imported patch 8190426-lazy-init-refinement-threads
rev 47864 : [mq]: 8190426-sangheon-review
@@ -28,19 +28,52 @@
#include "memory/allocation.hpp"
#include "utilities/globalDefinitions.hpp"
// Forward decl
class CardTableEntryClosure;
+class G1ConcurrentRefine;
class G1ConcurrentRefineThread;
class outputStream;
class ThreadClosure;
-class G1ConcurrentRefine : public CHeapObj<mtGC> {
+// Helper class for refinement thread management. Used to start, stop and
+// iterate over them.
+class G1ConcurrentRefineThreadControl VALUE_OBJ_CLASS_SPEC {
+ G1ConcurrentRefine* _cr;
+
G1ConcurrentRefineThread** _threads;
- uint _n_worker_threads;
+ uint _num_max_threads;
+
+ // Create the refinement thread for the given worker id.
+ // If initializing is true, ignore InjectGCWorkerCreationFailure.
+ G1ConcurrentRefineThread* create_refinement_thread(uint worker_id, bool initializing);
+public:
+ G1ConcurrentRefineThreadControl();
+ ~G1ConcurrentRefineThreadControl();
+
+ jint initialize(G1ConcurrentRefine* cr, uint num_max_threads);
+
+ // If there is a "successor" thread that can be activated given the current id,
+ // activate it.
+ void maybe_activate_next(uint cur_worker_id);
+
+ void print_on(outputStream* st) const;
+ void worker_threads_do(ThreadClosure* tc);
+ void stop();
+};
+
+// Controls refinement threads and their activation based on the number of completed
+// buffers currently available in the global dirty card queue.
+// Refinement threads pick work from the queue based on these thresholds. They are activated
+// gradually based on the amount of work to do.
+// Refinement thread n activates thread n+1 if the instance of this class determines there
+// is enough work available. Threads deactivate themselves if the current amount of
+// completed buffers falls below their individual threshold.
+class G1ConcurrentRefine : public CHeapObj<mtGC> {
+ G1ConcurrentRefineThreadControl _thread_control;
/*
- * The value of the update buffer queue length falls into one of 3 zones:
+ * The value of the completed dirty card queue length falls into one of 3 zones:
* green, yellow, red. If the value is in [0, green) nothing is
* done, the buffers are left unprocessed to enable the caching effect of the
* dirtied cards. In the yellow zone [green, yellow) the concurrent refinement
* threads are gradually activated. In [yellow, red) all threads are
* running. If the length becomes red (max queue length) the mutators start
@@ -50,11 +83,11 @@
* is turned off):
* 1) green = yellow = red = 0. In this case the mutator will process all
* buffers. Except for those that are created by the deferred updates
* machinery during a collection.
* 2) green = 0. Means no caching. Can be a good way to minimize the
- * amount of time spent updating rsets during a collection.
+ * amount of time spent updating remembered sets during a collection.
*/
size_t _green_zone;
size_t _yellow_zone;
size_t _red_zone;
size_t _min_yellow_zone_size;
@@ -67,28 +100,36 @@
// Update green/yellow/red zone values based on how well goals are being met.
void update_zones(double update_rs_time,
size_t update_rs_processed_buffers,
double goal_ms);
- // Update thread thresholds to account for updated zone values.
- void update_thread_thresholds();
+ static uint worker_id_offset();
+ void maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers);
- public:
+ jint initialize();
+public:
~G1ConcurrentRefine();
- // Returns a G1ConcurrentRefine instance if succeeded to create/initialize G1ConcurrentRefine and G1ConcurrentRefineThreads.
- // Otherwise, returns NULL with error code.
+ // Returns a G1ConcurrentRefine instance if succeeded to create/initialize the
+ // G1ConcurrentRefine instance. Otherwise, returns NULL with error code.
static G1ConcurrentRefine* create(jint* ecode);
void stop();
+ // Adjust refinement thresholds based on work done during the pause and the goal time.
void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms);
+ size_t activation_threshold(uint worker_id) const;
+ size_t deactivation_threshold(uint worker_id) const;
+ // Perform a single refinement step. Called by the refinement threads when woken up.
+ bool do_refinement_step(uint worker_id);
+
// Iterate over all concurrent refinement threads applying the given closure.
void threads_do(ThreadClosure *tc);
- static uint thread_num();
+ // Maximum number of refinement threads.
+ static uint max_num_threads();
void print_threads_on(outputStream* st) const;
size_t green_zone() const { return _green_zone; }
size_t yellow_zone() const { return _yellow_zone; }
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