1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
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 // Initialize an instance with the initial IHOP value in percent and the target
41 // occupancy. The target occupancy is the number of bytes when marking should
42 // be finished and reclaim started.
43 G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);
44 public:
45 virtual ~G1IHOPControl() { }
46
47 // Get the current non-young occupancy at which concurrent marking should start.
48 virtual size_t get_conc_mark_start_threshold() = 0;
49
50 // Update information about time during which allocations in the Java heap occurred,
51 // how large these allocations were in bytes, and an additional buffer.
52 // The allocations should contain any amount of space made unusable for further
53 // allocation, e.g. any waste caused by TLAB allocation, space at the end of
54 // humongous objects that can not be used for allocation, etc.
55 // Together with the target occupancy, this additional buffer should contain the
56 // difference between old gen size and total heap size at the start of reclamation,
57 // and space required for that reclamation.
58 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) = 0;
59 // Update the time spent in the mutator beginning from the end of initial mark to
60 // the first mixed gc.
61 virtual void update_marking_length(double marking_length_s) = 0;
62
63 virtual void print() = 0;
64 };
65
66 // The returned concurrent mark starting occupancy threshold is a fixed value
67 // relative to the maximum heap size.
68 class G1StaticIHOPControl : public G1IHOPControl {
69 // Most recent complete mutator allocation period in seconds.
70 double _last_allocation_time_s;
71 // Amount of bytes allocated during _last_allocation_time_s.
72 size_t _last_allocated_bytes;
73 // Most recent mutator time between the end of initial mark to the start of the
74 // first mixed gc.
75 double _last_marking_length_s;
76 public:
77 G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);
78
79 size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }
80
81 virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
82 assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
83 _last_allocation_time_s = allocation_time_s;
84 _last_allocated_bytes = allocated_bytes;
85 }
86
87 virtual void update_marking_length(double marking_length_s) {
88 assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
89 _last_marking_length_s = marking_length_s;
90 }
91
92 virtual void print();
93 #ifndef PRODUCT
94 static void test();
95 #endif
96 };
97
98 #endif // SHARE_VM_GC_G1_G1IHOPCONTROL_HPP