实验室比对zb值和zw值各表示什么？

一组数据中，待观察的结果相对于该组中其他观察值给该结果一个归一化的值，计算公式：

Z = （观察值－中间值）/ 归一化四分位数间距

ZB =（标准化和－中间值）/ 归一化四分位数间距

ZB =∣标准化差－中间值∣/ 归一化四分位数间距

归一化四分位数间距相当于标准差，参看稳健统计技术

查看GC 及jvm配置的方法：

1、查看GC的工具：

JVisualVM是JDK 6 update 7之后推出的一个工具，它类似于JProfiler的工具，基于此工具可查看内存的消耗情况、线程的执行状况及程序中消耗CPU、内存的动作。

在内存分析上，JVisualVM的最大好处是可通过安装VisualGC插件来分析GC趋势、内存消耗详细状况。

VisualGC的运行如图所示。

从图中可看到各区的内存消耗状况及GC Time的图表，其提供的Histogram视图对于调优也有很大帮助。

2、查看jvm配置

jinfo -flag HeapDumpBeforeFullGC? 29167? #查看HeapDumpBeforeFullGC?

jinfo: 查看和修改JVM参数?

Usage:?

jinfo ?

where is one of:?

-flag to print the value of the named VM flag?

-flag [+|-] to enable or disable the named VM flag?

-flag = to set the named VM flag to the given value?

-h | -help? to print this help message?

[@zw-90-156 ~]$ jmap 1282?

Attaching to process ID 1282, please wait...?

Debugger attached successfully.?

Server compiler detected.?

JVM version is 20.14-b01?

0x0000000040000000? 49K /opt/jdk1.6.0_43/bin/java?

0x00000037a5600000? 140K /lib64/ld-2.5.so?

0x00000037a5a00000? 1681K? /lib64/libc-2.5.so?

0x00000037a5e00000? 22K /lib64/libdl-2.5.so?

0x00000037a6200000? 600K /lib64/libm-2.5.so?

0x00000037a6600000? 142K /lib64/libpthread-2.5.so?

0x00000037a6e00000? 52K /lib64/librt-2.5.so?

0x00000037aa600000? 111K /lib64/libnsl-2.5.so?

0x00002aaaaaac3000? 64K /opt/jdk1.6.0_43/jre/lib/amd64/libverify.so?

0x00002aaaaabd2000? 229K /opt/jdk1.6.0_43/jre/lib/amd64/libjava.so?

0x00002aaaaad1a000? 52K /lib64/libnss_files-2.5.so?

0x00002aaaaaf25000? 90K /opt/jdk1.6.0_43/jre/lib/amd64/libzip.so?

0x00002aaaaf3d2000? 38K /opt/jdk1.6.0_43/jre/lib/amd64/libmanagement.so?

0x00002aaaaf4d9000? 110K /opt/jdk1.6.0_43/jre/lib/amd64/libnet.so?

0x00002ad21d600000? 47K /opt/jdk1.6.0_43/jre/lib/amd64/jli/libjli.so?

0x00002ad21d70d000? 13050K? /opt/jdk1.6.0_43/jre/lib/amd64/server/libjvm.so?

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