9 * This code is distributed in the hope that it will be useful, but WITHOUT
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_VM_GC_G1_G1IHOPCONTROL_HPP
26 #define SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
27
28 #include "memory/allocation.hpp"
29
30 // Base class for algorithms that calculate the heap occupancy at which
31 // concurrent marking should start. This heap usage threshold should be relative
32 // to old gen size.
33 class G1IHOPControl : public CHeapObj<mtGC> {
34 protected:
35 // The initial IHOP value relative to the target occupancy.
36 double _initial_ihop_percent;
37 // The target maximum occupancy of the heap.
38 size_t _target_occupancy;
39
40 // Most recent complete mutator allocation period in seconds.
41 double _last_allocation_time_s;
42 // Amount of bytes allocated during _last_allocation_time_s.
43 size_t _last_allocated_bytes;
44
45 // Initialize an instance with the initial IHOP value in percent and the target
46 // occupancy. The target occupancy is the number of bytes when marking should
47 // be finished and reclaim started.
48 G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);
73 };
74
75 // The returned concurrent mark starting occupancy threshold is a fixed value
76 // relative to the maximum heap size.
77 class G1StaticIHOPControl : public G1IHOPControl {
78 // Most recent mutator time between the end of initial mark to the start of the
79 // first mixed gc.
80 double _last_marking_length_s;
81 protected:
82 double last_marking_length_s() const { return _last_marking_length_s; }
83 public:
84 G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);
85
86 size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }
87
88 virtual void update_marking_length(double marking_length_s) {
89 assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
90 _last_marking_length_s = marking_length_s;
91 }
92
93 #ifndef PRODUCT
94 static void test();
95 #endif
96 };
97
98 #endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
|
9 * This code is distributed in the hope that it will be useful, but WITHOUT
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_VM_GC_G1_G1IHOPCONTROL_HPP
26 #define SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/numberSeq.hpp"
30
31 class G1Predictions;
32
33 // Base class for algorithms that calculate the heap occupancy at which
34 // concurrent marking should start. This heap usage threshold should be relative
35 // to old gen size.
36 class G1IHOPControl : public CHeapObj<mtGC> {
37 protected:
38 // The initial IHOP value relative to the target occupancy.
39 double _initial_ihop_percent;
40 // The target maximum occupancy of the heap.
41 size_t _target_occupancy;
42
43 // Most recent complete mutator allocation period in seconds.
44 double _last_allocation_time_s;
45 // Amount of bytes allocated during _last_allocation_time_s.
46 size_t _last_allocated_bytes;
47
48 // Initialize an instance with the initial IHOP value in percent and the target
49 // occupancy. The target occupancy is the number of bytes when marking should
50 // be finished and reclaim started.
51 G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);
76 };
77
78 // The returned concurrent mark starting occupancy threshold is a fixed value
79 // relative to the maximum heap size.
80 class G1StaticIHOPControl : public G1IHOPControl {
81 // Most recent mutator time between the end of initial mark to the start of the
82 // first mixed gc.
83 double _last_marking_length_s;
84 protected:
85 double last_marking_length_s() const { return _last_marking_length_s; }
86 public:
87 G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);
88
89 size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }
90
91 virtual void update_marking_length(double marking_length_s) {
92 assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
93 _last_marking_length_s = marking_length_s;
94 }
95
96 #ifndef PRODUCT
97 static void test();
98 #endif
99 };
100
101 // This algorithm tries to return a concurrent mark starting occupancy value that
102 // makes sure that during marking the given target occupancy is never exceeded,
103 // based on predictions of current allocation rate and time periods between
104 // initial mark and the first mixed gc.
105 class G1AdaptiveIHOPControl : public G1IHOPControl {
106 size_t _heap_reserve_percent; // Percentage of maximum heap capacity we should avoid to touch
107 size_t _heap_waste_percent; // Percentage of free heap that should be considered as waste.
108
109 const G1Predictions * _predictor;
110
111 TruncatedSeq _marking_times_s;
112 TruncatedSeq _allocation_rate_s;
113
114 size_t _last_allocation_bytes; // Most recent mutator allocation since last GC.
115 // The most recent unrestrained size of the young gen. This is used as an additional
116 // factor in the calculation of the threshold, as the threshold is based on
117 // non-young gen occupancy at the end of GC. For the IHOP threshold, we need to
118 // consider the young gen size during that time too.
119 // Since we cannot know what young gen sizes are used in the future, we will just
120 // use the current one. We expect that this one will be one with a fairly large size,
121 // as there is no marking or mixed gc that could impact its size too much.
122 size_t _last_unrestrained_young_size;
123
124 bool have_enough_data_for_prediction() const;
125
126 // The "actual" target threshold the algorithm wants to keep during and at the
127 // end of marking. This is typically lower than the requested threshold, as the
128 // algorithm needs to consider restrictions by the environment.
129 size_t actual_target_threshold() const;
130 protected:
131 virtual double last_marking_length_s() const { return _marking_times_s.last(); }
132 public:
133 G1AdaptiveIHOPControl(double ihop_percent,
134 size_t initial_target_occupancy,
135 G1Predictions const* predictor,
136 size_t heap_reserve_percent, // The percentage of total heap capacity that should not be tapped into.
137 size_t heap_waste_percent); // The percentage of the free space in the heap that we think is not usable for allocation.
138
139 virtual size_t get_conc_mark_start_threshold();
140
141 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size);
142 virtual void update_marking_length(double marking_length_s);
143
144 virtual void print();
145 #ifndef PRODUCT
146 static void test();
147 #endif
148 };
149
150 #endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
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