什么是ReservedCodeCacheSize和InitialCodeCacheSize？ [英] What are ReservedCodeCacheSize and InitialCodeCacheSize?

问题描述

有人可以解释一下JVM选项 ReservedCodeCacheSize 和 InitialCodeCacheSize 是什么？特别是何时/为什么我要改变它？我如何确定合适的尺寸？

Can someone please explain what the JVM option ReservedCodeCacheSize and InitialCodeCacheSize are? Specifically when/why would I want to change it? How do I decide what the right size is?

这就是文档所说的：

-XX：ReservedCodeCacheSize = 32m保留代码高速缓存大小（以字节为单位） - 最大代码高速缓存大小。 [Solaris 64位，amd64和-server x86：2048m;在1.5.0_06及更早版本中，Solaris 64位和64：1024m。]

-XX:ReservedCodeCacheSize=32m Reserved code cache size (in bytes) - maximum code cache size. [Solaris 64-bit, amd64, and -server x86: 2048m; in 1.5.0_06 and earlier, Solaris 64-bit and and64: 1024m.]

推荐答案

ReservedCodeCacheSize （和 InitialCodeCacheSize ）是Java Hotspot VM的（即时）编译器的选项。基本上它设置了编译器代码缓存的最大大小。

ReservedCodeCacheSize (and InitialCodeCacheSize) is an option for the (just-in-time) compiler of the Java Hotspot VM. Basically it sets the maximum size for the compiler's code cache.

缓存可能变满，导致出现如下警告：

The cache can become full, which results in warnings like the following:

Java HotSpot(TM) 64-Bit Server VM warning: CodeCache is full. Compiler has been disabled.
Java HotSpot(TM) 64-Bit Server VM warning: Try increasing the code cache size using -XX:ReservedCodeCacheSize=
Code Cache  [0x000000010958f000, 0x000000010c52f000, 0x000000010c58f000)
 total_blobs=15406 nmethods=14989 adapters=362 free_code_cache=835Kb largest_free_block=449792

当跟随 Java HotSpot（TM）客户端VM警告：异常java.lang.OutOfMemoryError发生调度信号SIGINT到处理程序 - VM可能需要强行终止。

何时设置此选项？

1. 当遇到Hotspot编译器失败时


2. 减少JVM所需的内存（因而冒着JIT编译器失败的风险）

通常你不会改变这个值。我认为默认值非常平衡，因为这个问题只在极少数情况下发生（在我的经验中）。

Normally you'd not change this value. I think the default values are quite good balanced because this problems occur on very rare occasions only (in my experince).

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