VisualVM

how to profile application startup with visualvm

由 喜你入骨 提交于 2019-12-17 15:31:04
问题 As far as i can tell, you can only profile a running application using VisualVM. Does anyone know of a way to profile the launch and startup of a java application using VisualVM? I'm convinced there must be a way, otherwise it would be a major oversight. Hoping I've just misread the documentation. Thanks, p. 回答1: Are you setting up the profiling using the `-Xrunjdwp" command-line option? If so, that option has a "suspend" parameter for just this purpose: True if the target VM is to be

How to memory profile in Java?

由 夙愿已清 提交于 2019-12-17 10:26:04
问题 I'm still learning the ropes of Java so sorry if there's a obvious answer to this. I have a program that is taking a ton of memory and I want to figure a way to reduce its usage, but after reading many SO questions I have the idea that I need to prove where the problem is before I start optimizing it. So here's what I did, I added a break point to the start of my program and ran it, then I started visualVM and had it profile the memory(I also did the same thing in netbeans just to compare the

JVM性能调优的6大步骤，及关键调优参数详解

由 好久不见. 提交于 2019-12-14 16:44:06
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> JVM内存调优 对JVM内存的系统级的调优主要的目的是减少GC的频率和Full GC的次数。 1.Full GC 会对整个堆进行整理，包括Young、Tenured和Perm。Full GC因为需要对整个堆进行回收，所以比较慢，因此应该尽可能减少Full GC的次数。 2.导致Full GC的原因 1)年老代（Tenured）被写满 调优时尽量让对象在新生代GC时被回收、让对象在新生代多存活一段时间和不要创建过大的对象及数组避免直接在旧生代创建对象 。 2)持久代Pemanet Generation空间不足 增大Perm Gen空间，避免太多静态对象 ， 控制好新生代和旧生代的比例 3)System.gc()被显示调用 垃圾回收不要手动触发，尽量依靠JVM自身的机制 在对JVM调优的过程中，很大一部分工作就是对于FullGC的调节，下面详细介绍对应JVM调优的方法和步骤。 JVM性能调优方法和步骤 1.监控GC的状态 使用各种JVM工具，查看当前日志，分析当前JVM参数设置，并且分析当前堆内存快照和gc日志，根据实际的各区域内存划分和GC执行时间，觉得是否进行优化。 举一个例子： 系统崩溃前的一些现象： 每次垃圾回收的时间越来越长，由之前的10ms延长到50ms左右，FullGC的时间也有之前的0.5s延长到4

Weblogic server startup profiling tools

由 断了今生、忘了曾经 提交于 2019-12-13 17:20:19
问题 What would be the best tool or approach if I want to profile my weblogic startup and tune start-up timing. Can it be done by visual vm or jprofiler or yourkit? What would be the best? 回答1: If you use JProfiler, use the integration wizard for Weblogic to configure profiling by selecting Session->Integration Wizards->New Server Integration from the main menu. On the "Startup mode" step, select the "Wait for a connection from the JProfiler GUI" option. When you start the session, the "Session

VisualVM profiler error: “Class JavaLaunchHelper is implemented in both ..bin/java and ..jre/lib”

由 孤人 提交于 2019-12-13 15:20:02
问题 When running the VisualVM profiler, it gives this error in the console of the program being run: objc[1145]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home/bin/java and /Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home/jre/lib/libinstrument.dylib. One of the two will be used. Which one is undefined. Profiler Agent: Waiting for connection on port 5140 (Protocol version: 15) Profiler Agent: Established connection with

Why aren't all methods displayed in VisualVM profiler?

由 青春壹個敷衍的年華 提交于 2019-12-12 07:57:07
问题 I am using VisualVM to see where my application is slow. But it does not show all methods, probably does not show all methods that delays the application. I have a realtime application (sound processing) and have a time deficiency in few hundreds of microseconds. Is it possible that VisualVM hides methods which are fast themselves? UPDATE 1 I found slow method by sampler and guessing. It was toString() method which was called from debug logging which was turned off, but consuming a time.

visualvm monitors memory usage

由 家住魔仙堡 提交于 2019-12-11 19:06:23
问题 in my tomcat startup, i set -xms , -xmx to 1GB. inside visualvm when i monitor memory when i do sampling of memory, it doesnt show accurate memory usage, until, if i press 'snapshot', and then the java classes that utilizing memory showing correct patterns and instances count. why like this? also, as i set tomcat memory to 1gb, memory keep on increasing ing zip-zat and go up aroudn 960mb. until i press "perform gc" and the memory back to 200mb.. do you think needed to create scheduler to

Optimizing java heap usage by String using StringBuffer , StringBuilder , String.intern()

由 时光怂恿深爱的人放手 提交于 2019-12-11 14:49:34
问题 I am monitoring the performance and CPU of a large java application , using VisualVM. When I look at its memory profile I see maximum heap (about 50%) is being used up by char arrays. Following is a screenshot of the memory profile: In the memory profile at any given time i see roughly about 9000 char[] objects. The application accepts a large file as input. The file roughly has about 80 lines each line consisting of 15-20 delimited config options. The application parses the file and stores

IntelliJ IDEA 的 main方法，for循环，syso的快捷键

由 谁都会走 提交于 2019-12-11 11:30:44
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 今天偶然发现了IntelliJ中 创建main函数的快捷键，依次还有for循环，System.out.println(); 在编写代码的时候直接输入psv就会看到一个psvm的提示，此时点击tab键一个main方法就写好了。 main方法 ： psvm 也就是public static void main的首字母。 for循环 依次还有在方法体内键入for会有一个fori的提示，选中然后tab键，就会自动创建一个for循环。 System.out.println() 如何像写一个System.out.println();就是sout 知道了这个规律，应该还有很多类似的用法。 更多的提示可以CTRL + j 可以查看，mac系统下是command＋j 。 推荐插件： （1）HighlightBracketPair：自动化高亮显示光标所在代码块对应的括号，可以定制颜色和形状 （2）Rainbow Brackets：彩色显示所有括号，对单行嵌套括号有用 （3）.ignore：生成各种ignore文件，一键创建git ignore文件的模板，免得自己去写 （4）Key promoter X ：快捷键提示插件，每进行一个鼠标操作，会提示你对应的快捷键是啥 （5）lombok：支持lombok的各种注解

“Protocol family unavailable” error while using VisualVM

由 限于喜欢 提交于 2019-12-11 07:48:28
问题 I am trying to use VisualVM to monitor my remote appliation. I started jstatd on port 1099 in my remote box. Now when I am trying to connect I get the following error in VisualVM log file. Any help to resolve this issue is appreciated. Thank you Chaitanya INFO [com.sun.tools.visualvm.jvmstat.application.JvmstatApplicationProvider]: Jvmstat connection to <myserver>[IP: <my IP>] failed. java.net.SocketException: Protocol family unavailable at java.net.PlainSocketImpl.socketConnect(Native Method
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