The document discusses the Z Garbage Collector (ZGC) introduced in JDK 11. ZGC provides scalable low-latency garbage collection for heap sizes in the terabytes by using concurrent, tracing GC techniques. It aims to reduce GC pause times to less than 10ms even for very large heaps, with low overhead of around 15%. The document covers how ZGC works, its implementation details like colored pointers and load barriers, and its performance compared to Parallel GC and G1 GC based on SPECjbb2015 benchmarks.

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The Z Garbage Collector
Scalable Low-Latency GC in JDK 11
David Buck
JVM Engineer
Java Platform Group, Oracle
March 28, 2019

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Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
2

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• JVM Sustaining Engineer
• OpenJDK Update Project
Maintainer
• JavaOne Rock Star
• Co-author of Oracle WebLogic
Server 11g 構築・運用ガイド
• @DavidBuckJP
• https://blogs.oracle.com/buck/
Who am I? バック デイビッド（左）

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Agenda
ZGC って何?
実装
パフォーマンス
ZGC の使い方
ロードマップ
1
2
3
4
5
4

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ZGC って何?
5

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まずは Z の意味。。。
6

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ＺＦＳ
7

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ＺＦＳ
Zettabyte File System
8

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Zettabyte
9

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Zettabyte?
10

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Zettabyte
== 1000^7 bytes
11

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Zettabyte
== 1000^7 bytes
== 1000 Exabytes
12

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Zettabyte
== 1000^7 bytes
== 1000 Exabytes
== 1,000,000 Petabytes
13

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Zettabyte
== 1000^7 bytes
== 1000 Exabytes
== 1,000,000 Petabytes
== 1,000,000,000 Terabytes
14

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Zettabyte != Zebibyte
1000^7 != 1024^7
15

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ZFS
最大 FS サイズ
256,000,000,000 yobibytes
最大ファイルサイズ
16 exbibytes
16

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ＺＦＳ ＺＧＣ
17

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ＺＦＳ ＺＧＣ
18

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ＺＦＳ ＺＧＣ
19

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ＺＦＳ ＺＧＣ
？？？
20

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ＺＧＣ
21

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JDK 11 以降の新しい GC
(実験的 Linux/x86_64 のみ) 22

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A Scalable Low-Latency Garbage Collector
23

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目的
複数 TB のヒープ 以下の停止時間
楽なチューニング 以下のオーバーヘッド
10msTB
15%
24

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ZGC のイロハ
Concurrent
Tracing
Compacting
Single Generation
25
Region 式
NUMA 対応
Load barriers
Colored pointers

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ZGC の特徴
ヒープと生存データのサイズが停止時間に
影響を及ぼさない
26

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ZGC の特徴
ルート参照の数が停止時間に
影響を及ぼす
(Java スレッドの数)
27

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コンカレント?
Serial Parallel CMS G1 ZGC
Marking
Relocation/Compaction
Reference Processing
Relocation Set Selection
StringTable Cleaning
JNI WeakRef Cleaning
JNI GlobalRefs Scanning
Class Unloading
Thread Stack Scanning
28

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コンカレント?
Serial Parallel CMS G1 ZGC
Marking - -
Relocation/Compaction - -
Reference Processing - -
Relocation Set Selection - -
StringTable Cleaning - -
JNI WeakRef Cleaning - -
JNI GlobalRefs Scanning - -
Class Unloading - -
Thread Stack Scanning - -
29

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コンカレント?
Serial Parallel CMS G1 ZGC
Marking - - ✔* ✔*
Relocation/Compaction - - - -
Reference Processing - - - -
Relocation Set Selection - - - -
StringTable Cleaning - - - -
JNI WeakRef Cleaning - - - -
JNI GlobalRefs Scanning - - - -
Class Unloading - - - -
Thread Stack Scanning - - - -
30
**) Old Gen Only

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コンカレント?
Serial Parallel CMS G1 ZGC
Marking - - ✔* ✔* ✔
Relocation/Compaction - - - - ✔
Reference Processing - - - - ✔
Relocation Set Selection - - - - ✔
StringTable Cleaning - - - - ✔
JNI WeakRef Cleaning - - - - ✔
JNI GlobalRefs Scanning - - - - ✔**
Class Unloading - - - - ✔**
Thread Stack Scanning - - - - -
31
**) Old Gen Only
**) JDK 12 以降

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実装
32

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Heap Address Space
ヒープのアドレス空間
Maps into
Max heap size (Xmx)
Large address space reservation
Heap Memory/RegionsHeap Memory/Regions
33

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
34

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Scan thread stacks
35

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Walk object graph
36

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Synchronization point
37

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Reference processing
Weak root cleaning
Relocation set selection
38

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Scan thread stacks
39

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
Compact heap
40

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
41

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ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
42
< 10 ms < 10 ms < 10 ms

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Colored Pointers （タグを含むポインター）
• ZGC の設計の基盤となる概念の一つ
• 利用されていないビットにメタデータを格納する
– 32-bit の JVM はサポート対象外
– CompressedOops もサポート対象外
43
Object のアドレス (42 bits, 4TB アドレス空間)
64-bit Object ポインター
未使用 (18 ビット)
Colors

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Heap Multi-Mapping on Linux/x86_64
Heap Remapped View
Heap Marked1 View
Heap Marked0 View
0x00007FFFFFFFFFFF (128TB)
0x0000140000000000 (20TB)
0x0000100000000000 (16TB)
0x00000C0000000000 (12TB)
0x0000080000000000 (8TB)
0x0000040000000000 (4TB)
0x0000000000000000
Heap Memory
Address Space
Same memory mapped in 3
different locations
Colored pointer (Remapped)
0x0000100012345678
Colorless pointer
0x0000000012345678
Colored pointer (Marked1)
0x0000080012345678
Colored pointer (Marked0)
0x0000040012345678
44

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Load Barrier
• 特定の処理にコードを組み込む
– Object の参照をヒープから読み込む場合
• 読み込んだポインタの色（color）が「正しい」かどうかを確認
– 正しくない場合、直す
45

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Load Barrier
String n = person.name; // Loading an object reference from heap
46
String name;
int age;
double height;
...
Person
String

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Load Barrier
String n = person.name; // Loading an object reference from heap
<load barrier needed here>
47
String name;
int age;
double height;
...
Person
String

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Load Barrier
String n = person.name; // Loading an object reference from heap
<load barrier needed here>
String p = n; // No barrier, not a load from heap
n.isEmpty(); // No barrier, not a load from heap
int age = person.age; // No barrier, not an object reference
48
String name;
int age;
double height;
...
Person
String

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Load Barrier
String n = person.name; // Loading an object reference from heap
<load barrier needed here>
49
String name;
int age;
double height;
...
Person
String

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Load Barrier
String n = person.name; // Loading an object reference from heap
if (n & bad_bit_mask) {
slow_path(register_for(n), address_of(person.name));
}
50
String name;
int age;
double height;
...
Person
String

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Load Barrier
mov 0x10(%rax), %rbx // String n = person.name;
test %rbx, (0x16)%r15 // Bad color?
jnz slow_path // Yes -> Enter slow path and
// mark/relocate/remap, adjust
// 0x10(%rax) and %rbx
51

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Load Barrier
mov 0x10(%rax), %rbx // String n = person.name;
test %rbx, (0x16)%r15 // Bad color?
jnz slow_path // Yes -> Enter slow path and
// mark/relocate/remap, adjust
// 0x10(%rax) and %rbx
~4% 実行オーバーヘッド SPECjbb®2015
52

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パフォーマンス
53

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Mode: Composite
Heap Size: 128G
OS: Oracle Linux 7.4
HW: Intel Xeon E5-2690 2.9GHz
2 sockets, 16 cores (32 hw-threads)
SPECjbb®2015 is a registered trademark of the Standard Performance
Evaluation Corporation (spec.org). The actual results are not represented
as compliant because the SUT may not meet SPEC's requirements for
general availability.
SPECjbb®2015 – Score
54
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
ZGC Parallel G1
(Higher is better)
max-JOPS (Throughput) critical-JOPS (Throughput with latency requirements)

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Mode: Composite
Heap Size: 128G
OS: Oracle Linux 7.4
HW: Intel Xeon E5-2690 2.9GHz
2 sockets, 16 cores (32 hw-threads)
SPECjbb®2015 is a registered trademark of the Standard Performance
Evaluation Corporation (spec.org). The actual results are not represented
as compliant because the SUT may not meet SPEC's requirements for
general availability.
SPECjbb®2015 – Score
55
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
ZGC Parallel G1
(Higher is better)
max-JOPS (Throughput) critical-JOPS (Throughput with latency requirements)
50%
29%

56. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
0
100
200
300
400
500
600
ZGC Parallel G1
GCPauseTimes(ms)
Linear scale
(Lower is better)
Average 95th percentile 99th percentile 99.9th percentile Max
SPECjbb®2015 – Pause Times
56

57. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
1
10
100
1000
ZGC Parallel G1
GCPauseTimes(ms)
Logarithmic scale
(Lower is better)
Average 95th percentile 99th percentile 99.9th percentile Max
SPECjbb®2015 – Pause Times
57

58. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
1
10
100
1000
ZGC Parallel G1
GCPauseTimes(ms)
Logarithmic scale
(Lower is better)
Average 95th percentile 99th percentile 99.9th percentile Max
SPECjbb®2015 – Pause Times
58
1.96
1.10
156
306
211
544

59. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
1
10
100
1000
ZGC Parallel G1
GCPauseTimes(ms)
Logarithmic scale
(Lower is better)
Average 95th percentile 99th percentile 99.9th percentile Max
SPECjbb®2015 – Pause Times
59
1.96
1.10
156
306
211
544

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ZGC の使い方
60

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有効にする
-XX:+UseZGC
61

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有効にする
-XX:+UnlockExperimentalVMOptions
-XX:+UseZGC
62

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チューニング
63

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チューニング
-Xmx<size>
最大のヒープサイズ
64

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チューニング
-Xmx<size>
-XX:ConcGCThreads=<number>
（必要に応じて）GC のワーカースレッド
65

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チューニング
-Xmx<size>
-XX:ConcGCThreads=<number>
これだけ？
66

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ログ出力
-Xlog:gc （基本）
-Xlog:gc* （詳細）
67

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Garbage Collection (Proactive) 13426M(10%)->2492M(2%)
Garbage Collection (Allocation Rate) 87676M(67%)->19578M(15%)
Garbage Collection (Allocation Rate) 55302M(42%)->17646M(13%)
Garbage Collection (Allocation Rate) 61794M(47%)->26794M(20%)
Garbage Collection (Allocation Rate) 60856M(46%)->31926M(24%)
Garbage Collection (Allocation Rate) 52744M(40%)->38050M(29%)
Garbage Collection (Allocation Rate) 42542M(32%)->32204M(25%)
Garbage Collection (Allocation Rate) 49974M(38%)->8534M(7%)
Garbage Collection (System.gc()) 8534M(7%)->282M(0%)
Garbage Collection (Allocation Rate) 95454M(73%)->25660M(20%)
Garbage Collection (Allocation Rate) 42478M(32%)->23812M(18%)
Garbage Collection (Allocation Rate) 56714M(43%)->29090M(22%)
Garbage Collection (Allocation Rate) 62802M(48%)->28648M(22%)
Garbage Collection (Allocation Rate) 59748M(46%)->23770M(18%)
Garbage Collection (Allocation Rate) 74946M(57%)->23284M(18%)
Garbage Collection (System.gc()) 44902M(34%)->422M(0%)
Garbage Collection (Allocation Rate) 94510M(72%)->20456M(16%)
Garbage Collection (Allocation Rate) 59694M(46%)->25834M(20%)
Garbage Collection (Allocation Rate) 63494M(48%)->29128M(22%)
Garbage Collection (Allocation Rate) 59034M(45%)->27094M(21%)
Garbage Collection (Allocation Rate) 66110M(50%)->25278M(19%)
Garbage Collection (Allocation Rate) 73410M(56%)->27968M(21%)
Garbage Collection (Allocation Rate) 70010M(53%)->32236M(25%)
Garbage Collection (Allocation Rate) 64444M(49%)->27612M(21%)
Garbage Collection (Allocation Rate) 64484M(49%)->29910M(23%)
Garbage Collection (Allocation Rate) 64128M(49%)->33184M(25%)
Garbage Collection (Allocation Rate) 59148M(45%)->27800M(21%)
Garbage Collection (Allocation Rate) 63104M(48%)->27976M(21%)
Garbage Collection (Allocation Rate) 64418M(49%)->34390M(26%)
Garbage Collection (Allocation Rate) 52284M(40%)->30654M(23%)
Garbage Collection (Allocation Rate) 58746M(45%)->32028M(24%)
Garbage Collection (Allocation Rate) 59468M(45%)->32804M(25%)
Garbage Collection (Allocation Rate) 53342M(41%)->18436M(14%)
68

69. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Proactive) 13426M(10%)->2492M(2%)
Garbage Collection (Allocation Rate) 87676M(67%)->19578M(15%)
Garbage Collection (Allocation Rate) 55302M(42%)->17646M(13%)
Garbage Collection (Allocation Rate) 61794M(47%)->26794M(20%)
Garbage Collection (Allocation Rate) 60856M(46%)->31926M(24%)
Garbage Collection (Allocation Rate) 52744M(40%)->38050M(29%)
Garbage Collection (Allocation Rate) 42542M(32%)->32204M(25%)
Garbage Collection (Allocation Rate) 49974M(38%)->8534M(7%)
Garbage Collection (System.gc()) 8534M(7%)->282M(0%)
Garbage Collection (Allocation Rate) 95454M(73%)->25660M(20%)
Garbage Collection (Allocation Rate) 42478M(32%)->23812M(18%)
Garbage Collection (Allocation Rate) 56714M(43%)->29090M(22%)
Garbage Collection (Allocation Rate) 62802M(48%)->28648M(22%)
Garbage Collection (Allocation Rate) 59748M(46%)->23770M(18%)
Garbage Collection (Allocation Rate) 74946M(57%)->23284M(18%)
Garbage Collection (System.gc()) 44902M(34%)->422M(0%)
Garbage Collection (Allocation Rate) 94510M(72%)->20456M(16%)
Garbage Collection (Allocation Rate) 59694M(46%)->25834M(20%)
Garbage Collection (Allocation Rate) 63494M(48%)->29128M(22%)
Garbage Collection (Allocation Rate) 59034M(45%)->27094M(21%)
Garbage Collection (Allocation Rate) 66110M(50%)->25278M(19%)
Garbage Collection (Allocation Rate) 73410M(56%)->27968M(21%)
Garbage Collection (Allocation Rate) 70010M(53%)->32236M(25%)
Garbage Collection (Allocation Rate) 64444M(49%)->27612M(21%)
Garbage Collection (Allocation Rate) 64484M(49%)->29910M(23%)
Garbage Collection (Allocation Rate) 64128M(49%)->33184M(25%)
Garbage Collection (Allocation Rate) 59148M(45%)->27800M(21%)
Garbage Collection (Allocation Rate) 63104M(48%)->27976M(21%)
Garbage Collection (Allocation Rate) 64418M(49%)->34390M(26%)
Garbage Collection (Allocation Rate) 52284M(40%)->30654M(23%)
Garbage Collection (Allocation Rate) 58746M(45%)->32028M(24%)
Garbage Collection (Allocation Rate) 59468M(45%)->32804M(25%)
Garbage Collection (Allocation Rate) 53342M(41%)->18436M(14%)
69
Garbage Collection (Allocation Rate) 95454M(73%)->25660M(20%)

70. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Allocation Rate)
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms
Load: 15.77/10.68/9.93
MMU: 2ms/0.0%, 5ms/57.5%, 10ms/78.7%, 20ms/87.8%, 50ms/93.7%, 100ms/96.8%
Mark: 4 stripe(s), 2 proactive flush(es), 1 terminate flush(es), 0 completion(s), 0 continuation(s)
Relocation: Successful, 867M relocated
NMethods: 3209 registered, 1559 unregistered
Soft: 466881 encountered, 0 discovered, 0 enqueued
Weak: 5421 encountered, 3526 discovered, 1742 enqueued
Final: 55 encountered, 6 discovered, 0 enqueued
Phantom: 74 encountered, 59 discovered, 0 enqueued
Mark Start Mark End Relocate Start Relocate End High Low
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%) 126306M (96%) 5866M (4%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%) 125134M (95%) 4694M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%) - -
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%) - -
Garbage: - 121623M (93%) 103353M (79%) 127M (0%) - -
Reclaimed: - - 18270M (14%) 121496M (93%) - -
Garbage Collection (Allocation Rate) 123346M(94%)->4704M(4%)
70

71. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Allocation Rate)
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms
Load: 15.77/10.68/9.93
MMU: 2ms/0.0%, 5ms/57.5%, 10ms/78.7%, 20ms/87.8%, 50ms/93.7%, 100ms/96.8%
Mark: 4 stripe(s), 2 proactive flush(es), 1 terminate flush(es), 0 completion(s), 0 continuation(s)
Relocation: Successful, 867M relocated
NMethods: 3209 registered, 1559 unregistered
Soft: 466881 encountered, 0 discovered, 0 enqueued
Weak: 5421 encountered, 3526 discovered, 1742 enqueued
Final: 55 encountered, 6 discovered, 0 enqueued
Phantom: 74 encountered, 59 discovered, 0 enqueued
Mark Start Mark End Relocate Start Relocate End High Low
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%) 126306M (96%) 5866M (4%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%) 125134M (95%) 4694M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%) - -
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%) - -
Garbage: - 121623M (93%) 103353M (79%) 127M (0%) - -
Reclaimed: - - 18270M (14%) 121496M (93%) - -
Garbage Collection (Allocation Rate) 123346M(94%)->4704M(4%)
71
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms

72. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Allocation Rate)
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms
Load: 15.77/10.68/9.93
MMU: 2ms/0.0%, 5ms/57.5%, 10ms/78.7%, 20ms/87.8%, 50ms/93.7%, 100ms/96.8%
Mark: 4 stripe(s), 2 proactive flush(es), 1 terminate flush(es), 0 completion(s), 0 continuation(s)
Relocation: Successful, 867M relocated
NMethods: 3209 registered, 1559 unregistered
Soft: 466881 encountered, 0 discovered, 0 enqueued
Weak: 5421 encountered, 3526 discovered, 1742 enqueued
Final: 55 encountered, 6 discovered, 0 enqueued
Phantom: 74 encountered, 59 discovered, 0 enqueued
Mark Start Mark End Relocate Start Relocate End High Low
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%) 126306M (96%) 5866M (4%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%) 125134M (95%) 4694M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%) - -
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%) - -
Garbage: - 121623M (93%) 103353M (79%) 127M (0%) - -
Reclaimed: - - 18270M (14%) 121496M (93%) - -
Garbage Collection (Allocation Rate) 123346M(94%)->4704M(4%)
72
Mark Start Mark End Relocate Start Relocate End
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%)
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%)
Garbage: - 121623M (93%) 103353M (79%) 127M (0%)
Reclaimed: - - 18270M (14%) 121496M (93%)

73. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ZGC Phases
Concurrent
Mark/Remap
Pause Mark End Pause Relocate StartPause Mark Start
Concurrent
Prepare for Reloc.
Concurrent
Relocate
GC Cycle
73

74. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Allocation Rate)
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms
Load: 15.77/10.68/9.93
MMU: 2ms/0.0%, 5ms/57.5%, 10ms/78.7%, 20ms/87.8%, 50ms/93.7%, 100ms/96.8%
Mark: 4 stripe(s), 2 proactive flush(es), 1 terminate flush(es), 0 completion(s), 0 continuation(s)
Relocation: Successful, 867M relocated
NMethods: 3209 registered, 1559 unregistered
Soft: 466881 encountered, 0 discovered, 0 enqueued
Weak: 5421 encountered, 3526 discovered, 1742 enqueued
Final: 55 encountered, 6 discovered, 0 enqueued
Phantom: 74 encountered, 59 discovered, 0 enqueued
Mark Start Mark End Relocate Start Relocate End High Low
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%) 126306M (96%) 5866M (4%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%) 125134M (95%) 4694M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%) - -
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%) - -
Garbage: - 121623M (93%) 103353M (79%) 127M (0%) - -
Reclaimed: - - 18270M (14%) 121496M (93%) - -
Garbage Collection (Allocation Rate) 123346M(94%)->4704M(4%)
74
Mark Start Mark End Relocate Start Relocate End
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%)
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%)
Garbage: - 121623M (93%) 103353M (79%) 127M (0%)
Reclaimed: - - 18270M (14%) 121496M (93%)

75. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Garbage Collection (Allocation Rate)
Pause Mark Start 0.949ms
Concurrent Mark 1151.425ms
Pause Mark End 0.882ms
Concurrent Process Non-Strong References 0.367ms
Concurrent Reset Relocation Set 18.090ms
Concurrent Destroy Detached Pages 0.002ms
Concurrent Select Relocation Set 12.295ms
Concurrent Prepare Relocation Set 70.922ms
Pause Relocate Start 1.419ms
Concurrent Relocate 645.941ms
Load: 15.77/10.68/9.93
MMU: 2ms/0.0%, 5ms/57.5%, 10ms/78.7%, 20ms/87.8%, 50ms/93.7%, 100ms/96.8%
Mark: 4 stripe(s), 2 proactive flush(es), 1 terminate flush(es), 0 completion(s), 0 continuation(s)
Relocation: Successful, 867M relocated
NMethods: 3209 registered, 1559 unregistered
Soft: 466881 encountered, 0 discovered, 0 enqueued
Weak: 5421 encountered, 3526 discovered, 1742 enqueued
Final: 55 encountered, 6 discovered, 0 enqueued
Phantom: 74 encountered, 59 discovered, 0 enqueued
Mark Start Mark End Relocate Start Relocate End High Low
Capacity: 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%) 131072M (100%)
Reserve: 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%) 72M (0%)
Free: 7654M (6%) 5898M (4%) 24018M (18%) 126296M (96%) 126306M (96%) 5866M (4%)
Used: 123346M (94%) 125102M (95%) 106982M (82%) 4704M (4%) 125134M (95%) 4694M (4%)
Live: - 1722M (1%) 1722M (1%) 1722M (1%) - -
Allocated: - 1796M (1%) 1962M (1%) 3766M (3%) - -
Garbage: - 121623M (93%) 103353M (79%) 127M (0%) - -
Reclaimed: - - 18270M (14%) 121496M (93%) - -
Garbage Collection (Allocation Rate) 123346M(94%)->4704M(4%)
75

76. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
GC Statistics （統計）
=== Garbage Collection Statistics =======================================================================================================================
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Collector: Garbage Collection Cycle 1906.804 / 1906.804 1871.019 / 2184.368 2764.747 / 4655.377 2764.747 / 4655.377 ms
Contention: Mark Segment Reset Contention 3 / 24 0 / 34 0 / 73 0 / 73 ops/s
Contention: Mark SeqNum Reset Contention 0 / 0 0 / 0 0 / 2 0 / 2 ops/s
Contention: Relocation Contention 27 / 275 9 / 1137 14 / 9460 14 / 9460 ops/s
Critical: Allocation Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: Allocation Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Critical: GC Locker Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: GC Locker Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Allocation Rate 1458 / 1672 1089 / 1904 1679 / 7914 1679 / 7914 MB/s
Memory: Heap Used After Mark 125102 / 125102 97411 / 125102 70566 / 125102 70566 / 125102 MB
Memory: Heap Used After Relocation 4704 / 4704 4019 / 4814 17042 / 34092 17042 / 34092 MB
Memory: Heap Used Before Mark 123346 / 123346 95981 / 123346 61669 / 123346 61669 / 123346 MB
Memory: Heap Used Before Relocation 106982 / 106982 85095 / 106982 60136 / 106982 60136 / 106982 MB
Memory: Out Of Memory 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Page Cache Flush 0 / 0 0 / 0 0 / 0 0 / 0 MB/s
Memory: Page Cache Hit L1 710 / 1037 499 / 1037 771 / 3777 771 / 3777 ops/s
Memory: Page Cache Hit L2 12 / 77 3 / 179 5 / 517 5 / 517 ops/s
Memory: Page Cache Miss 8 / 81 19 / 651 29 / 1932 29 / 1932 ops/s
Memory: Undo Object Allocation Failed 1 / 12 0 / 18 0 / 64 0 / 64 ops/s
Memory: Undo Object Allocation Succeeded 26 / 263 9 / 1137 13 / 9460 13 / 9460 ops/s
Memory: Undo Page Allocation 3 / 30 5 / 249 9 / 1027 9 / 1027 ops/s
Phase: Concurrent Destroy Detached Pages 0.002 / 0.002 0.001 / 0.002 0.041 / 2.230 0.041 / 2.230 ms
Phase: Concurrent Mark 1151.425 / 1151.425 1163.417 / 1452.750 1584.987 / 3028.289 1584.987 / 3028.289 ms
Phase: Concurrent Mark Continue 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Phase: Concurrent Prepare Relocation Set 70.922 / 70.922 67.627 / 74.532 81.298 / 374.926 81.298 / 374.926 ms
Phase: Concurrent Process Non-Strong References 0.367 / 0.367 0.391 / 0.463 0.394 / 0.774 0.394 / 0.774 ms
Phase: Concurrent Relocate 645.941 / 645.941 602.340 / 645.941 1051.985 / 2198.100 1051.985 / 2198.100 ms
Phase: Concurrent Reset Relocation Set 18.090 / 18.090 13.636 / 18.090 11.832 / 28.342 11.832 / 28.342 ms
Phase: Concurrent Select Relocation Set 12.295 / 12.295 15.162 / 28.735 20.960 / 57.464 20.960 / 57.464 ms
Phase: Pause Mark End 0.882 / 0.882 0.997 / 1.095 0.941 / 1.199 0.941 / 1.199 ms
Phase: Pause Mark Start 0.949 / 0.949 0.875 / 0.983 0.832 / 1.013 0.832 / 1.013 ms
Phase: Pause Relocate Start 1.419 / 1.419 1.532 / 2.091 1.474 / 2.127 1.474 / 2.127 ms
Subphase: Concurrent Mark 1151.055 / 1151.287 1162.724 / 1452.499 1059.510 / 3028.035 1059.510 / 3028.035 ms
Subphase: Concurrent Mark Idle 1.058 / 1.060 1.088 / 2.320 2.727 / 22.115 2.727 / 22.115 ms
Subphase: Concurrent Mark Try Flush 0.779 / 1.862 0.603 / 5.829 8.556 / 50.035 8.556 / 50.035 ms
Subphase: Concurrent Mark Try Terminate 0.849 / 1.062 0.940 / 2.321 2.766 / 45.114 2.766 / 45.114 ms
76

77. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
=== Garbage Collection Statistics =======================================================================================================================
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Collector: Garbage Collection Cycle 1906.804 / 1906.804 1871.019 / 2184.368 2764.747 / 4655.377 2764.747 / 4655.377 ms
Contention: Mark Segment Reset Contention 3 / 24 0 / 34 0 / 73 0 / 73 ops/s
Contention: Mark SeqNum Reset Contention 0 / 0 0 / 0 0 / 2 0 / 2 ops/s
Contention: Relocation Contention 27 / 275 9 / 1137 14 / 9460 14 / 9460 ops/s
Critical: Allocation Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: Allocation Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Critical: GC Locker Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: GC Locker Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Allocation Rate 1458 / 1672 1089 / 1904 1679 / 7914 1679 / 7914 MB/s
Memory: Heap Used After Mark 125102 / 125102 97411 / 125102 70566 / 125102 70566 / 125102 MB
Memory: Heap Used After Relocation 4704 / 4704 4019 / 4814 17042 / 34092 17042 / 34092 MB
Memory: Heap Used Before Mark 123346 / 123346 95981 / 123346 61669 / 123346 61669 / 123346 MB
Memory: Heap Used Before Relocation 106982 / 106982 85095 / 106982 60136 / 106982 60136 / 106982 MB
Memory: Out Of Memory 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Page Cache Flush 0 / 0 0 / 0 0 / 0 0 / 0 MB/s
Memory: Page Cache Hit L1 710 / 1037 499 / 1037 771 / 3777 771 / 3777 ops/s
Memory: Page Cache Hit L2 12 / 77 3 / 179 5 / 517 5 / 517 ops/s
Memory: Page Cache Miss 8 / 81 19 / 651 29 / 1932 29 / 1932 ops/s
Memory: Undo Object Allocation Failed 1 / 12 0 / 18 0 / 64 0 / 64 ops/s
Memory: Undo Object Allocation Succeeded 26 / 263 9 / 1137 13 / 9460 13 / 9460 ops/s
Memory: Undo Page Allocation 3 / 30 5 / 249 9 / 1027 9 / 1027 ops/s
Phase: Concurrent Destroy Detached Pages 0.002 / 0.002 0.001 / 0.002 0.041 / 2.230 0.041 / 2.230 ms
Phase: Concurrent Mark 1151.425 / 1151.425 1163.417 / 1452.750 1584.987 / 3028.289 1584.987 / 3028.289 ms
Phase: Concurrent Mark Continue 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Phase: Concurrent Prepare Relocation Set 70.922 / 70.922 67.627 / 74.532 81.298 / 374.926 81.298 / 374.926 ms
Phase: Concurrent Process Non-Strong References 0.367 / 0.367 0.391 / 0.463 0.394 / 0.774 0.394 / 0.774 ms
Phase: Concurrent Relocate 645.941 / 645.941 602.340 / 645.941 1051.985 / 2198.100 1051.985 / 2198.100 ms
Phase: Concurrent Reset Relocation Set 18.090 / 18.090 13.636 / 18.090 11.832 / 28.342 11.832 / 28.342 ms
Phase: Concurrent Select Relocation Set 12.295 / 12.295 15.162 / 28.735 20.960 / 57.464 20.960 / 57.464 ms
Phase: Pause Mark End 0.882 / 0.882 0.997 / 1.095 0.941 / 1.199 0.941 / 1.199 ms
Phase: Pause Mark Start 0.949 / 0.949 0.875 / 0.983 0.832 / 1.013 0.832 / 1.013 ms
Phase: Pause Relocate Start 1.419 / 1.419 1.532 / 2.091 1.474 / 2.127 1.474 / 2.127 ms
...
77

78. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
=== Garbage Collection Statistics =======================================================================================================================
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Collector: Garbage Collection Cycle 1906.804 / 1906.804 1871.019 / 2184.368 2764.747 / 4655.377 2764.747 / 4655.377 ms
Contention: Mark Segment Reset Contention 3 / 24 0 / 34 0 / 73 0 / 73 ops/s
Contention: Mark SeqNum Reset Contention 0 / 0 0 / 0 0 / 2 0 / 2 ops/s
Contention: Relocation Contention 27 / 275 9 / 1137 14 / 9460 14 / 9460 ops/s
Critical: Allocation Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: Allocation Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Critical: GC Locker Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: GC Locker Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Allocation Rate 1458 / 1672 1089 / 1904 1679 / 7914 1679 / 7914 MB/s
Memory: Heap Used After Mark 125102 / 125102 97411 / 125102 70566 / 125102 70566 / 125102 MB
Memory: Heap Used After Relocation 4704 / 4704 4019 / 4814 17042 / 34092 17042 / 34092 MB
Memory: Heap Used Before Mark 123346 / 123346 95981 / 123346 61669 / 123346 61669 / 123346 MB
Memory: Heap Used Before Relocation 106982 / 106982 85095 / 106982 60136 / 106982 60136 / 106982 MB
Memory: Out Of Memory 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Page Cache Flush 0 / 0 0 / 0 0 / 0 0 / 0 MB/s
Memory: Page Cache Hit L1 710 / 1037 499 / 1037 771 / 3777 771 / 3777 ops/s
Memory: Page Cache Hit L2 12 / 77 3 / 179 5 / 517 5 / 517 ops/s
Memory: Page Cache Miss 8 / 81 19 / 651 29 / 1932 29 / 1932 ops/s
Memory: Undo Object Allocation Failed 1 / 12 0 / 18 0 / 64 0 / 64 ops/s
Memory: Undo Object Allocation Succeeded 26 / 263 9 / 1137 13 / 9460 13 / 9460 ops/s
Memory: Undo Page Allocation 3 / 30 5 / 249 9 / 1027 9 / 1027 ops/s
Phase: Concurrent Destroy Detached Pages 0.002 / 0.002 0.001 / 0.002 0.041 / 2.230 0.041 / 2.230 ms
Phase: Concurrent Mark 1151.425 / 1151.425 1163.417 / 1452.750 1584.987 / 3028.289 1584.987 / 3028.289 ms
Phase: Concurrent Mark Continue 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Phase: Concurrent Prepare Relocation Set 70.922 / 70.922 67.627 / 74.532 81.298 / 374.926 81.298 / 374.926 ms
Phase: Concurrent Process Non-Strong References 0.367 / 0.367 0.391 / 0.463 0.394 / 0.774 0.394 / 0.774 ms
Phase: Concurrent Relocate 645.941 / 645.941 602.340 / 645.941 1051.985 / 2198.100 1051.985 / 2198.100 ms
Phase: Concurrent Reset Relocation Set 18.090 / 18.090 13.636 / 18.090 11.832 / 28.342 11.832 / 28.342 ms
Phase: Concurrent Select Relocation Set 12.295 / 12.295 15.162 / 28.735 20.960 / 57.464 20.960 / 57.464 ms
Phase: Pause Mark End 0.882 / 0.882 0.997 / 1.095 0.941 / 1.199 0.941 / 1.199 ms
Phase: Pause Mark Start 0.949 / 0.949 0.875 / 0.983 0.832 / 1.013 0.832 / 1.013 ms
Phase: Pause Relocate Start 1.419 / 1.419 1.532 / 2.091 1.474 / 2.127 1.474 / 2.127 ms
...
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Allocation Rate 1458 / 1672 1089 / 1904 1679 / 7914 1679 / 7914 MB/s
78

79. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
=== Garbage Collection Statistics =======================================================================================================================
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Collector: Garbage Collection Cycle 1906.804 / 1906.804 1871.019 / 2184.368 2764.747 / 4655.377 2764.747 / 4655.377 ms
Contention: Mark Segment Reset Contention 3 / 24 0 / 34 0 / 73 0 / 73 ops/s
Contention: Mark SeqNum Reset Contention 0 / 0 0 / 0 0 / 2 0 / 2 ops/s
Contention: Relocation Contention 27 / 275 9 / 1137 14 / 9460 14 / 9460 ops/s
Critical: Allocation Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: Allocation Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Critical: GC Locker Stall 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Critical: GC Locker Stall 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Allocation Rate 1458 / 1672 1089 / 1904 1679 / 7914 1679 / 7914 MB/s
Memory: Heap Used After Mark 125102 / 125102 97411 / 125102 70566 / 125102 70566 / 125102 MB
Memory: Heap Used After Relocation 4704 / 4704 4019 / 4814 17042 / 34092 17042 / 34092 MB
Memory: Heap Used Before Mark 123346 / 123346 95981 / 123346 61669 / 123346 61669 / 123346 MB
Memory: Heap Used Before Relocation 106982 / 106982 85095 / 106982 60136 / 106982 60136 / 106982 MB
Memory: Out Of Memory 0 / 0 0 / 0 0 / 0 0 / 0 ops/s
Memory: Page Cache Flush 0 / 0 0 / 0 0 / 0 0 / 0 MB/s
Memory: Page Cache Hit L1 710 / 1037 499 / 1037 771 / 3777 771 / 3777 ops/s
Memory: Page Cache Hit L2 12 / 77 3 / 179 5 / 517 5 / 517 ops/s
Memory: Page Cache Miss 8 / 81 19 / 651 29 / 1932 29 / 1932 ops/s
Memory: Undo Object Allocation Failed 1 / 12 0 / 18 0 / 64 0 / 64 ops/s
Memory: Undo Object Allocation Succeeded 26 / 263 9 / 1137 13 / 9460 13 / 9460 ops/s
Memory: Undo Page Allocation 3 / 30 5 / 249 9 / 1027 9 / 1027 ops/s
Phase: Concurrent Destroy Detached Pages 0.002 / 0.002 0.001 / 0.002 0.041 / 2.230 0.041 / 2.230 ms
Phase: Concurrent Mark 1151.425 / 1151.425 1163.417 / 1452.750 1584.987 / 3028.289 1584.987 / 3028.289 ms
Phase: Concurrent Mark Continue 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 0.000 / 0.000 ms
Phase: Concurrent Prepare Relocation Set 70.922 / 70.922 67.627 / 74.532 81.298 / 374.926 81.298 / 374.926 ms
Phase: Concurrent Process Non-Strong References 0.367 / 0.367 0.391 / 0.463 0.394 / 0.774 0.394 / 0.774 ms
Phase: Concurrent Relocate 645.941 / 645.941 602.340 / 645.941 1051.985 / 2198.100 1051.985 / 2198.100 ms
Phase: Concurrent Reset Relocation Set 18.090 / 18.090 13.636 / 18.090 11.832 / 28.342 11.832 / 28.342 ms
Phase: Concurrent Select Relocation Set 12.295 / 12.295 15.162 / 28.735 20.960 / 57.464 20.960 / 57.464 ms
Phase: Pause Mark End 0.882 / 0.882 0.997 / 1.095 0.941 / 1.199 0.941 / 1.199 ms
Phase: Pause Mark Start 0.949 / 0.949 0.875 / 0.983 0.832 / 1.013 0.832 / 1.013 ms
Phase: Pause Relocate Start 1.419 / 1.419 1.532 / 2.091 1.474 / 2.127 1.474 / 2.127 ms
...
Last 10s Last 10m Last 10h Total
Avg / Max Avg / Max Avg / Max Avg / Max
Pause Mark End 0.882 / 0.882 0.997 / 1.095 0.941 / 1.199 0.941 / 1.199 ms
Pause Mark Start 0.949 / 0.949 0.875 / 0.983 0.832 / 1.013 0.832 / 1.013 ms
Pause Relocate Start 1.419 / 1.419 1.532 / 2.091 1.474 / 2.127 1.474 / 2.127 ms
79

80. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
80

81. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
81

82. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
-XX:+UnlockExperimentalVMOptions
82

83. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
• 長期
– 世代別
– １ミリ秒以下の停止時間
– 他のプラットフォームのサポート
– Graal JIT の対応
83

84. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
• 長期
– 世代別
– １ミリ秒以下の停止時間
– 他のプラットフォームのサポート
– Graal JIT の対応
世代別
• より速いアロケーション速度
• ヒープオーバーヘッドを抑える
• CPU 使用量を減らす
84

85. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
• 長期
– 世代別
– １ミリ秒以下の停止時間
– 他のプラットフォームのサポート
– Graal JIT の対応
１ミリ秒以下の停止時間
• 出来るはず
• ルート参照の数を減らす
• Time-to-Safepoint、など
85

86. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
• 長期
– 世代別
– １ミリ秒以下の停止時間
– 他のプラットフォームのサポート
– Graal JIT の対応
他のプラットフォーム
• macOS?
• Windows?
• Aarch64?
86

87. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ロードマップ
• 短期
– 正式サポート
• 長期
– 世代別
– １ミリ秒以下の停止時間
– 他のプラットフォームのサポート
– Graal JIT の対応
87

88. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
是非参加してください！
88

89. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ZGC プロジェクト
zgc-dev@openjdk.java.net
http://wiki.openjdk.java.net/display/zgc/Main
Follow, Participate, Give Feedback
89

90. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ZGC Project
http://hg.openjdk.java.net/jdk/jdk
http://hg.openjdk.java.net/zgc/zgc
ソースコード
90

91. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
ありがとうございます!
91

92. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
質問?
92