文章目录
- 一次生产环境高内存
- 查看堆外内存
- 阿尔萨斯
- 安装使用
- greys
- 安装使用
- 其他命令
- perf-tools
- 堆外内存
一次生产环境高内存 sudo -u admin /java/bin/jmap -histo:live 37 | head -10 | sort -r -k3
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jmap -heap pid
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top
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查看堆外内存
- 推荐java visualVM ，安装Buffer Pools来监测
@Test
public void test() throws Exception{
while(true) {
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(1024 * 1024 * 1);
}
}
禁用System.gc，直接OOM
-verbose:gc -XX:+PrintGCDetails -XX:MaxDirectMemorySize=50m -XX:+DisableExplicitGC
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开启-XX:+ExplicitGCInvokesConcurrent，允许System.gc生效
【查看堆外内存】
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- sa-jdi.jar
java -classpath .\sa-jdi.jar sun.jvm.hotspot.HSDB 图形界面 windows无法连接pid
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手动触发full gc，（ sudo -u admin /bin/jmap -histo:live 38 |head -10 ）之后
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dashboard
direct 显示40m
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thread
finalizer 8
gc 2
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安装使用
curl -L https://alibaba.github.io/arthas/install.sh | sh
yum install xinetd telnet telnet-server -y
sudo -u admin -EH ./as.sh
greys 安装使用
wget -c http://ompc.oss.aliyuncs.com/greys/release/greys-1.7.6.4-bin.zip
unzip
cd greys
sh ./install-local.sh 安装
开启端口
sudo -u admin ./ga.sh 33
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./greys.sh 开启命令行模式
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输入jvm查看内存情况
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totalusedfreesharedbuff/cacheavailable
Mem:15G8.8G6.0G1.0M700M6.4G
Swap:0B0B0B
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https://www.jianshu.com/p/c76747997ade
https://www.jianshu.com/p/4e96beb37935
其他命令
quit 退出
shutdown 关闭
perf-tools /home/admin/busuac/gref/lib
export LD_PRELOAD=/home/admin/busuac/gperf/lib/libtcmalloc.so
export HEAPPROFILE=/home/admin/busuac
./configure --prefix=安装目录
/home/admin/busuac/gperf/lib
堆外内存
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画重点
private static long maxDirectMemory0() {
long maxDirectMemory = 0;
try {
// Try to get from sun.misc.VM.maxDirectMemory() which should be most accurate.
Class vmClass = Class.forName("sun.misc.VM", true, getSystemClassLoader());
Method m = vmClass.getDeclaredMethod("maxDirectMemory");
maxDirectMemory = ((Number) m.invoke(null)).longValue();
} catch (Throwable ignored) {
// Ignore
}if (maxDirectMemory > 0) {
return maxDirectMemory;
}try {
// Now try to get the JVM option (-XX:MaxDirectMemorySize) and parse it.
// Note that we are using reflection because Android doesn't have these classes.
Class mgmtFactoryClass = Class.forName(
"java.lang.management.ManagementFactory", true, getSystemClassLoader());
Class runtimeClass = Class.forName(
"java.lang.management.RuntimeMXBean", true, getSystemClassLoader());
Object runtime = mgmtFactoryClass.getDeclaredMethod("getRuntimeMXBean").invoke(null);
@SuppressWarnings("unchecked")
List> vmArgs = (List>) runtimeClass.getDeclaredMethod("getInputArguments").invoke(runtime);
for (int i = vmArgs.size() - 1;
i >= 0;
i --) {
Matcher m = MAX_DIRECT_MEMORY_SIZE_ARG_PATTERN.matcher(vmArgs.get(i));
if (!m.matches()) {
continue;
}maxDirectMemory = Long.parseLong(m.group(1));
switch (m.group(2).charAt(0)) {
case 'k': case 'K':
maxDirectMemory *= 1024;
break;
case 'm': case 'M':
maxDirectMemory *= 1024 * 1024;
break;
case 'g': case 'G':
maxDirectMemory *= 1024 * 1024 * 1024;
break;
}
break;
}
} catch (Throwable ignored) {
// Ignore
}if (maxDirectMemory <= 0) {
maxDirectMemory = Runtime.getRuntime().maxMemory();
logger.debug("maxDirectMemory: {} bytes (maybe)", maxDirectMemory);
} else {
logger.debug("maxDirectMemory: {} bytes", maxDirectMemory);
}return maxDirectMemory;
}
https://segmentfault.com/a/1190000013688744
