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11月前
JDK8u221 + Docker,Heap Usage 远远小于分配的NewSize、OldSize
我们的某个应用跑在JDK8u221上,使用Docker
容器资源配置如下:
resources:
limits:
cpu: '4'
memory: 4Gi
requests:
cpu: '1'
memory: 2Gi
JVM启动信息如下:
-server -XX:InitialRAMPercentage=60.0 -XX:MinRAMPercentage=60.0 -XX:MaxRAMPercentage=60.0 -Xss256k -XX:SurvivorRatio=3 -XX:+UseFastAccessorMethods
jmap -heap 信息如下:
Heap Configuration:
MinHeapFreeRatio = 0
MaxHeapFreeRatio = 100
MaxHeapSize = 2577399808 (2458.0MB)
NewSize = 858783744 (819.0MB)
MaxNewSize = 858783744 (819.0MB)
OldSize = 1718616064 (1639.0MB)
NewRatio = 2
SurvivorRatio = 3
MetaspaceSize = 21807104 (20.796875MB)
CompressedClassSpaceSize = 1073741824 (1024.0MB)
MaxMetaspaceSize = 17592186044415 MB
G1HeapRegionSize = 0 (0.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 156762112 (149.5MB)
used = 91814128 (87.56077575683594MB)
free = 64947984 (61.93922424316406MB)
58.5690807738033% used
From Space:
capacity = 3145728 (3.0MB)
used = 2719744 (2.59375MB)
free = 425984 (0.40625MB)
86.45833333333333% used
To Space:
capacity = 5242880 (5.0MB)
used = 0 (0.0MB)
free = 5242880 (5.0MB)
0.0% used
PS Old Generation
capacity = 246415360 (235.0MB)
used = 210939648 (201.167724609375MB)
free = 35475712 (33.832275390625MB)
85.60328706781915% used
44662 interned Strings occupying 5495696 bytes.
该应用已经跑了好几天
观察到:
- Eden Space capacity + From Space capacity + To Space capacity 远远小于 NewSize
- PS Old Generation capacity 远远小于 OldSize
为什么分配了这么多空间,JVM它不用,而是在这么小的新生代里不断GC呢?
请教一下各位大佬,这是什么原因,有什么文档可供参考吗?
以前没有使用容器的时候,使用-Xms -Xmn -Xmx 印象中不会出现这样的问题
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