JMH generator: the best practice of the annotation processor in the Java class library
JMH generator: the best practice of the annotation processor in the Java class library
Summary:
With the development of the Java language, the annotation processor has become a powerful tool to generate high -performance and efficient code.JMH (Java Microbenchmark Harness) generator is an excellent annotation processor in the Java class library for writing and running micro -foundation tests.This article will introduce the best practice of the JMH generator, including using the JMH generator to write the basic principles of high -performance micro -base standard test, the steps of using the JMH generator for performance analysis and optimization, and some practical example code.
1. Introduction to JMH generator
The JMH generator is an annotation processor in the Java class library for compiling and running micro -base standards.It provides a simple and reliable method to evaluate and compare the performance of Java code.The JMH generator has high scalability and flexibility, and can be configured for different test scenarios, such as the execution time, memory usage, and locking competition.Using the JMH generator can more accurately measure the performance of the code, thereby performing accurate performance optimization.
2. Use the JMH generator to write the basic principles of high -performance micro -base standard testing
(1) Select the appropriate benchmark test sample: The benchmark test sample should represent the expected use situation in the real scene and cover the possible boundaries.
(2) Avoid interference factors: Micro -based standards should minimize external interference factors, such as I/O operations, network communication, etc.
(3) Accurately measure the performance of code: Use the annotation of the JMH generator to measure the performance of the code to avoid manual timing or other inaccurate methods.
(4) Repeat test to obtain reliable data: multiple tests are performed to obtain reliable performance data, and the automated test function provided by the JMH generator can be used.
3. The steps of using the JMH generator for performance analysis and optimization
(1) Writing the benchmark test method: Use the annotation of the JMH generator to mark the method of testing and set the corresponding test parameters.
(2) Operation benchmark test: Use the JMH generator to run the benchmark test, the execution time of the collection method.
(3) Analysis of performance data: Use the analysis tools provided by the JMH generator, such as flame charts, performance reports, etc. to determine the performance bottleneck in the code.
(4) Optimization and reconstruction code: Code optimization and reconstruction based on the analysis results. The goal is to improve the performance of the code and eliminate potential performance bottlenecks.
(5) Retree the benchmark test: Use the JMH generator to re -run the benchmark test, verify the effect of optimization, and use iterative optimization as needed.
4. Example code
Below is a sample code that uses JMH generator to write micro -based standard tests:
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;
// State the benchmark test class
@State(Scope.Thread)
public class MyBenchmark {
private int[] array;
@Setup
public void setup() {
// Initialize test data
array = new int[1000];
for (int i = 0; i < array.length; i++) {
array[i] = i;
}
}
@Benchmark
@Fork(value = 1)
@Warmup(iterations = 3)
@Measurement(iterations = 5)
public int sumArray() {
int sum = 0;
for (int i : array) {
sum += i;
}
return sum;
}
@TearDown
public void tearDown() {
// Clean up resources
array = null;
}
}
The above code demonstrates how to use the JMH generator to write a benchmark test method.The test data is initialized in the `setup ()` method, and adds annotations to the method of `Sumarray ()` to mark it as a method that needs to be performed for performance testing.`@Fork` Number of times to perform the number of times each test method is performed,`@warmup` indicates the number of preheats, `@Measurement` indicates the real number of measured times.Clean the resource in the method of `Teardown ().
This is the basic framework that uses the JMH generator to run the benchmark test, which can be configured and optimized accordingly according to specific needs.
in conclusion:
Through the JMH generator, we can write high -performance, accurate micro -base accuracy, and further improve the execution efficiency of the Java code through performance analysis and optimization.Using the JMH generator can help developers understand the performance characteristics of the code in depth and optimize the bottleneck targeted.In the actual development process, reasonable use of the JMH generator can improve the quality and performance of the code, making the application more efficient and stable.
references:
1. Java Microbenchmark Harness (JMH) official document: https://openjdk.java.net/projects/code-tools/jmh//
2. "Java High Performance Programming", Guo Junyi.
