IBM J9VM的默认堆大小是多少？ [英] What's the default heap size for IBM's J9VM?

问题描述

我安装了IBM的J9 VM（build 2.3，J2RE 1.5.0 IBM J9 2.3）。获得OOM后，堆转储的大小为383MB。 JVM有多少堆？

我问的原因是400MB堆转储似乎对我预期的默认64MB堆有点多，但我没有t指定任何-Xm选项。 J9是否使用不同的默认堆大小？如果是这样，我怎么知道它是什么？

解决方案

根据文档，默认最小和最大堆大小取决于平台。在大多数平台上，默认-Xms为4M。 Linux的默认-Xmx是实际内存的一半，最小16 MB，最大512 MB，对于Windows，它是实际内存的一半，最小16 MB，最大2 GB。 / p>

I have IBM's J9 VM (build 2.3, J2RE 1.5.0 IBM J9 2.3) installed. After getting an OOM, the size of the heap dump is 383MB. How much heap does the JVM have?

The reason why I ask is that a 400MB heap dump seems a bit much for the default 64MB heap that I expect but I didn't specify any -Xm options. Does J9 use a different default heap size? If so, how can I find out what it is?

解决方案

According to the documentation, the default minimum and maximum heap sizes are platform-dependent. On most platforms, default -Xms is 4M. Default -Xmx for Linux is "Half the real memory with a minimum of 16 MB and a maximum of 512 MB", and for Windows, it's "Half the real memory with a minimum of 16 MB and a maximum of 2 GB".

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