In the development process of Java program, it is unavoidable to encounter memory usage, performance bottleneck and so on. javaprofiler Tools Help developers locate these issues quickly and effectively, making them an important tool in the Java development process. At present, there are many kinds of JavaProfiler
Compared with static code analysis, profiling is a dynamic analysis method for studying program behavior by collecting information during program running. The purpose is to locate the part of the program that needs to be optimized to improve the program running speed or memory usage efficiency. The following three methods are used to collect information when a program is running:
Event method: for
survivor area. Then tidy up the two districts of survivor.
Full GCOrganize the entire heap, including young, tenured and perm. The full GC is slower than the scavenge GC, so the full GC should be minimized as much as possible. The full GC may be caused by the following reasons:
Dynamic changes in the domain allocation policy of the heap after the last GC
System.GC () is displayed call
Perm field is full
Tenured was written full
In the process of developing Java programs, it is unavoidable to encounter problems such as memory usage, performance bottleneck and so on. The Java Profiler Tool helps developers locate these issues quickly and efficiently, making it an important tool in the Java development process. At present, there are a variety of
Author Joachim Haagen skeie translator Li Yong posted on November 9, 2011 Domain Language Development theme tools, performance and scalability, Java Tag Performance tuning, open source Java sharing |
More than once, we all had the idea of trying to find out what was going on in the bottom of a running program. This need may be due to slow service,
not improve efficiency, but will reduce efficiency, because there is a lock upgrade process, this time will need to-xx:-usebiasedlocking to disable the biased lock. Here are the comparison of these types of locks:
Locking and unlocking does not require additional consumption, and the execution of a non-synchronous method is less than the nanosecond-level gap.
Gen, which can be shorter on pause times. Use-XX:+USEPARALLELOLDGC to enable parallel compacting Collector in the JVM startup parameters.
Concurrent mark-sweep (CMS) Collector: The concurrency flag clears the garbage collector, for young Gen uses the same garbage collection strategy as parallel Collector, for tenured Gen, Garbage-collected garbage-flagged threads are at the same time as the application thread, while garbage removal requires suspending the application thread, but the pause
Advantages of professional tools
Once you know that a memory leak occurs, you need more professional tools to find out why the leak occurs. The JVM won't tell you. These majorsThe tool obtains memory system information from JVM in two ways: jvmti and byte codeInstrumentation ).
tool is tightly integrated into jrockit JVM, with very low overhead and easy access to virtual machine heap.
Advantages of professional tools
Once you know that a memory leak occurs, you need more professional tools to find out why the leak occurs. The JVM won't tell you. These professional tools obtain information ab
-a full-featured Java profiling tool dedicated to analyzing j2se and J2EE applications. It combines CPU, thread, and memory analysis in a powerful application. Jprofiler provides many ide integration and application server integration functions. Jprofiler's intuitive GUI allows you to find performance bottlenecks, capture mem
The Sun JDK also publishes a number of profiling tools with the release, which are basically based on the JVM Mangeapi and Sun JVM Attach API implementations, so what features can be found in the instructions for the JVM Manage API. Let's take a look at:First, functional tools1. JPS: Lists the process ID and process name of all JVM processes and implements the principle visible sun JVM Attach API2. Jinfo: P
Jstack (view threads), Jmap (view memory), and Jstat (profiling) commandsAn article shared by colleagues inside the companySee an example of using Jstack to view a deadlock on the weekend. Last night summed up the Jstack (view thread), Jmap (view memory), and Jstat (performance analysis) commands. For everyone's reference1. Jstack1.1 Jstack can get information on
Sometimes we need to perform performance tests on software programs that we develop, and some profilers tools are needed. 5 useful. NET profilers are listed below:1. JetBrains DottraceJetBrains Dottrace is a. NET Apps performance and memory Profile tool. It lets you quickly detect your. NET 1.0 to 4.5 application performance bottlenecks.Learn more about the Dottrace ' s product website2. ANTS Performance Pr
) To hold Java classes, objects, and static members, all objects created in a Java program are allocated space in the heap, and the heap is used only to store objects. The application accesses the heap data through a reference that resides within the stack, and a JVM process can have only one heap. The JVM sets the initial and maximum values of the heap, respectively, with the-XMS and-XMX parameters.This di
Java itself provides a rich variety of methods and tools to help developers view and analyze the state of the GC and its JVM memory, while the open source community has tools to view and analyze the status of GC and JVM memory.With these analyses, you can troubleshoot memory
Original: http://yalung929.blog.163.com/blog/static/203898225201212981731971/Introduction: The top command, as one of the most commonly used performance analysis tools under Linux, can monitor and collect CPU,IO , and memory usage of the process. For example, we can Use the top command to get how much virtual memory (VIRT), physical
------iOS training, Java training, Android training, iOS learning technology blog, looking forward to communicating with you------Bitwise AND 1101110 1011010110101 000100——————— ---------------0100100 000100in situ and 1, remained unchanged; and 0, all 0Therefore, you can let the original number of a bit with 1, according to the result can determine whether the bit is 0 or 1, and the result is only 0 or 1 A1==1//a is odd because the last digit of the
and tools (IO infrastructure, data structure, thread management, security, monitoring, etc.)– Dynamic memory allocation and management with garbage collection
Your JVM can reside in a number of operating systems (Solaris, AIX, Windows, and so on.) And can be configured on your physical server, you can install 1 to more JVM processes on each physical/virtual server.
Interaction between the JVM and the mid
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