10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP
27
28 #include "gc/shenandoah/shenandoahNumberSeq.hpp"
29 #include "gc/shenandoah/shenandoahPadding.hpp"
30 #include "memory/allocation.hpp"
31
32 class ShenandoahHeap;
33
34 #define PACING_PROGRESS_UNINIT (-1)
35 #define PACING_PROGRESS_ZERO ( 0)
36
37 /**
38 * ShenandoahPacer provides allocation pacing mechanism.
39 *
40 * Currently it implements simple tax-and-spend pacing policy: GC threads provide
41 * credit, allocating thread spend the credit, or stall when credit is not available.
42 */
43 class ShenandoahPacer : public CHeapObj<mtGC> {
44 private:
45 ShenandoahHeap* _heap;
46 double _last_time;
47 TruncatedSeq* _progress_history;
48 Monitor* _wait_monitor;
49 ShenandoahSharedFlag _need_notify_waiters;
50
51 // Set once per phase
52 volatile intptr_t _epoch;
53 volatile double _tax_rate;
54
55 // Heavily updated, protect from accidental false sharing
56 shenandoah_padding(0);
57 volatile intptr_t _budget;
58 shenandoah_padding(1);
59
60 // Heavily updated, protect from accidental false sharing
61 shenandoah_padding(2);
62 volatile intptr_t _progress;
63 shenandoah_padding(3);
64
65 public:
66 ShenandoahPacer(ShenandoahHeap* heap) :
67 _heap(heap),
68 _last_time(os::elapsedTime()),
69 _progress_history(new TruncatedSeq(5)),
70 _wait_monitor(new Monitor(Mutex::safepoint-1, "ShenandoahWaitMonitor_lock", true)),
71 _epoch(0),
72 _tax_rate(1),
73 _budget(0),
74 _progress(PACING_PROGRESS_UNINIT) {}
75
76 void setup_for_idle();
77 void setup_for_mark();
78 void setup_for_evac();
79 void setup_for_updaterefs();
80
81 void setup_for_reset();
82
83 inline void report_mark(size_t words);
84 inline void report_evac(size_t words);
85 inline void report_updaterefs(size_t words);
86
87 inline void report_alloc(size_t words);
88
89 bool claim_for_alloc(size_t words, bool force);
90 void pace_for_alloc(size_t words);
91 void unpace_for_alloc(intptr_t epoch, size_t words);
92
93 void notify_waiters();
94
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHPACER_HPP
27
28 #include "gc/shenandoah/shenandoahNumberSeq.hpp"
29 #include "gc/shenandoah/shenandoahPadding.hpp"
30 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
31 #include "memory/allocation.hpp"
32 #include "runtime/task.hpp"
33
34 class ShenandoahHeap;
35 class ShenandoahPacer;
36
37
38 // Periodic task to notify blocked paced waiters.
39 class ShenandoahPeriodicPacerNotifyTask : public PeriodicTask {
40 private:
41 ShenandoahPacer* const _pacer;
42 public:
43 explicit ShenandoahPeriodicPacerNotifyTask(ShenandoahPacer* pacer) :
44 PeriodicTask(PeriodicTask::min_interval),
45 _pacer(pacer) { }
46
47 void task() override;
48 };
49
50
51 #define PACING_PROGRESS_UNINIT (-1)
52 #define PACING_PROGRESS_ZERO ( 0)
53
54 /**
55 * ShenandoahPacer provides allocation pacing mechanism.
56 *
57 * Currently it implements simple tax-and-spend pacing policy: GC threads provide
58 * credit, allocating thread spend the credit, or stall when credit is not available.
59 */
60 class ShenandoahPacer : public CHeapObj<mtGC> {
61 private:
62 ShenandoahHeap* _heap;
63 double _last_time;
64 TruncatedSeq* _progress_history;
65 Monitor* _wait_monitor;
66 ShenandoahSharedFlag _need_notify_waiters;
67 ShenandoahPeriodicPacerNotifyTask _notify_waiters_task;
68
69 // Set once per phase
70 volatile intptr_t _epoch;
71 volatile double _tax_rate;
72
73 // Heavily updated, protect from accidental false sharing
74 shenandoah_padding(0);
75 volatile intptr_t _budget;
76 shenandoah_padding(1);
77
78 // Heavily updated, protect from accidental false sharing
79 shenandoah_padding(2);
80 volatile intptr_t _progress;
81 shenandoah_padding(3);
82
83 public:
84 explicit ShenandoahPacer(ShenandoahHeap* heap) :
85 _heap(heap),
86 _last_time(os::elapsedTime()),
87 _progress_history(new TruncatedSeq(5)),
88 _wait_monitor(new Monitor(Mutex::safepoint-1, "ShenandoahWaitMonitor_lock", true)),
89 _notify_waiters_task(this),
90 _epoch(0),
91 _tax_rate(1),
92 _budget(0),
93 _progress(PACING_PROGRESS_UNINIT) {
94 _notify_waiters_task.enroll();
95 }
96
97 void setup_for_idle();
98 void setup_for_mark();
99 void setup_for_evac();
100 void setup_for_updaterefs();
101
102 void setup_for_reset();
103
104 inline void report_mark(size_t words);
105 inline void report_evac(size_t words);
106 inline void report_updaterefs(size_t words);
107
108 inline void report_alloc(size_t words);
109
110 bool claim_for_alloc(size_t words, bool force);
111 void pace_for_alloc(size_t words);
112 void unpace_for_alloc(intptr_t epoch, size_t words);
113
114 void notify_waiters();
115
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