"long" Multiply and Assignment: 38 Nanoseconds per Step

This section provides a tutorial example on how to perform benchmark tests to find out how long a multiply and assignment loop will take to run. The answer is 38 nanoseconds per step.

The next test is to measure the multiply operation performance. Here is the test method:

/**
 * BenchmarkTestLong.java
 * Copyright (c) 2010, HerongYang.com, All Rights Reserved.
 */
class BenchmarkTestLong {
...
   // Test method for a multiply operation in a loop
   public static long multiply(int steps, BenchmarkRunner runner) {
      long x = 0;
      long i = 0;
      long last = steps;
      runner.startTimer();
      for (i=0; i<last; i++) {
         x = i*3;
      }
      runner.stopTimer();
      return x;
   }
}

Here are test results:

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 10
...
Runs: 100, Ave: 276, Min: 251, Max: 279 - Per step in nanoseconds

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 100
...
Runs: 100, Ave: 61, Min: 59, Max: 64 - Per step in nanoseconds

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 1000
...
Runs: 100, Ave: 40, Min: 40, Max: 41 - Per step in nanoseconds

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 10000
...
Runs: 100, Ave: 38, Min: 38, Max: 44 - Per step in nanoseconds

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 100000
...
Runs: 100, Ave: 38, Min: 38, Max: 38 - Per step in nanoseconds

C:\herong\jvm>java -Xint -Xms100m -Xmx100m BenchmarkRunner 
BanchmarkTestLong multiply 10000 100 1000000
...
Runs: 100, Ave: 38, Min: 38, Max: 40 - Per step in nanoseconds

Conclusions based on the test result:

Last update: 2010.

Table of Contents

 About This Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 Sun's JVM - Java HotSpot VM

 JRockit JVM 28.2.7 by Oracle Corporation

 JVM Runtime Data Areas

 Memory Management and Garbage Collectors

 Garbage Collection Tests

 JVM Stack, Frame and Stack Overflow

 Thread Testing Program and Result

 CPU Impact of Multi-Thread Applications

 I/O Impact of Multi-Thread Applications

 CDS (Class Data Sharing)

 Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

Micro Benchmark Tests on "long" Operations

 "long" Empty Loop: 25 Nanoseconds per Step

 "long" Assignment Only: 24 Nanoseconds per Step

 "long" Shift and Assignment: 30 Nanoseconds per Step

 "long" Add and Assignment: 34 Nanoseconds per Step

"long" Multiply and Assignment: 38 Nanoseconds per Step

 "long" Division and Assignment: 53 Nanoseconds per Step

 Performance Comparisons between "int" and "long"

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

 Outdated Tutorials

 References

 PDF Printing Version