- jstat -gc
S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT 43136.0 43648.0 33153.9 0.0 43776.0 21516.2 230208.0 159622.8 167296.0 97949.0 54 0.743 6 1.818 2.561 - jstat -gcutil
S0 S1 E O P YGC YGCT FGC FGCT GCT 76.86 0.00 49.15 69.34 58.55 54 0.743 6 1.818 2.561 - jstat -gccause
S0 S1 E O P YGC YGCT FGC FGCT GCT LGCC GCC 4.36 0.00 24.82 83.77 59.00 56 0.778 6 1.818 2.597 unknown GCCause No GC - jmap -heap
Attaching to process ID
6313
, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is
20.6
-b01
using thread-local object allocation.
Parallel GC with
8
thread(s)
Heap Configuration:
MinHeapFreeRatio =
40
MaxHeapFreeRatio =
70
MaxHeapSize =
402653184
(
384
.0MB)
NewSize =
1310720
(
1
.25MB)
MaxNewSize =
17592186044415
MB
OldSize =
5439488
(
5
.1875MB)
NewRatio =
2
SurvivorRatio =
8
PermSize =
21757952
(
20
.75MB)
MaxPermSize =
268435456
(
256
.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity =
44826624
(
42
.75MB)
used =
22032640
(
21
.011962890625MB)
free =
22793984
(
21
.738037109375MB)
49.1507903874269
% used
From Space:
capacity =
44171264
(
42
.125MB)
used =
33949608
(
32
.376869201660156MB)
free =
10221656
(
9
.748130798339844MB)
76.85903668049889
% used
To Space:
capacity =
44695552
(
42
.625MB)
used =
0
(
0
.0MB)
free =
44695552
(
42
.625MB)
0.0
% used
PS Old Generation
capacity =
235732992
(
224
.8125MB)
used =
163453776
(
155
.8816680908203MB)
free =
72279216
(
68
.93083190917969MB)
69.33852347659509
% used
PS Perm Generation
capacity =
171311104
(
163
.375MB)
used =
100301240
(
95
.65471649169922MB)
free =
71009864
(
67
.72028350830078MB)
58.549176123457826
% used
- jmap -histo
num #instances #bytes
class
name
----------------------------------------------
1
:
750317
56395560
[C
2
:
129895
21499600
<constMethodKlass>
3
:
83179
21015088
[I
4
:
129895
17699800
<methodKlass>
5
:
12505
15631136
<constantPoolKlass>
6
:
459347
14699104
java.lang.String
7
:
224473
12661344
<symbolKlass>
8
:
382084
12226688
java.util.HashMap$Entry
9
:
18654
10661752
[B
10
:
12505
10024032
<instanceKlassKlass>
. . . .
. . . .
. . . .
Total
4315507
315914176
- jmap -dump:live,file=dump.bin,format=b,生成一个二进制文件,使用MemoryAnalyzer打开进行分析
解释
-
缩写 解释 S0C 当前survivor space 0 的容量 (KB). S1C 当前survivor space 1 的容量 (KB). S0U survivor space 0 使用量 (KB). S1U survivor space 1 使用量 (KB). EC 当前eden space 的容量 (KB). EU eden space 使用量 (KB). OC 当前old space 的容量 (KB). OU old space 使用量 (KB). PC 当前permanent space 的容量 (KB). PU permanent space 使用量 (KB). YGC young generation gc 事件的次数 YGCT young generation gc 事件的时间 FGC full gc 事件的次数 FGCT full gc事件的时间 GCT 整个gc事件的时间 -
缩写 解释 S0 survivor space 0 使用的比例 S1 survivor space 1 使用的比例 E Eden space使用的比例 O Old space 使用的比例 P Permanent space使用的比例 LGCC 上次gc的原因 GCC 当前gc的原因