JDK11"jstat -gc <PID>"中的"CGC"和"CGCT"是什么意思？

Question

有两个项目称为 CGC 和 CGCT。我找不到描述它们含义的文档和手册页。

# jstat -gc 139934
 S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT    CGC    CGCT     GCT   
 0.0   15360.0  0.0   15360.0 113664.0  9216.0   88064.0    23552.0   82304.0 80084.2 10112.0 9360.4     10    0.157   0      0.000   6      0.018    0.175

# java -version 
openjdk version "11.0.2" 2019-01-15 LTS
OpenJDK Runtime Environment Corretto-11.0.2.9.3 (build 11.0.2+9-LTS)
OpenJDK 64-Bit Server VM Corretto-11.0.2.9.3 (build 11.0.2+9-LTS, mixed mode

我使用了默认的 jvm 参数。

#jhsdb jmap --heap --pid 139934 | grep GC
Garbage-First (G1) GC with 13 thread(s)

Answer 1

据我了解 link, the first C in CGC and CGCT stands for "concurrent", so based on the description from the docs 对于 GC 和 GCT：

GCT: Total garbage collection time.

我会说 CGTC 是 "Concurrent Total Garbage Collection" 而 CGC 是 "Concurrent Garbage Collection"。

Answer 2

根据this，CGC和CGCT是并发垃圾收集器ZGC的标志。所以这两项可以解释为：

CGC: Concurrent GC Count
CGCT: Concurrent GC Collection Time

JDK11"jstat -gc <PID>"中的"CGC"和"CGCT"是什么意思？

What's the meaning of "CGC" and "CGCT" in JDK11 "jstat -gc <PID>"?

java

jvm

java-11

jstat