Aprof

Aprof

by Devexperts

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java.util.LinkedHashMap$Entry: 18,880 (0%) bytes in 590 (0%) objects (avg size 32 bytes)
    java.util.LinkedHashMap.createEntry: 18,560 (98%) bytes in 580 (98%) objects
        com.devexperts.aprof.AProfAgent.go: 18,432 (99%) bytes in 576 (99%) objects
        java.util.HashMap.put: 128 (0%) bytes in 4 (0%) objects
            java.io.ExpiringCache.put: 128 (100%) bytes in 4 (100%) objects
    java.util.LinkedHashMap.init: 320 (1%) bytes in 10 (1%) objects
        com.devexperts.aprof.AProfAgent.go: 128 (40%) bytes in 4 (40%) objects
        java.util.HashMap.<init>: 128 (40%) bytes in 4 (40%) objects
            java.util.LinkedHashMap.<init>: 128 (100%) bytes in 4 (100%) objects
        java.util.HashSet.<init>: 64 (20%) bytes in 2 (20%) objects
            java.util.LinkedHashSet.<init>: 64 (100%) bytes in 2 (100%) objects
java.lang.Long: 18,336 (0%) bytes in 1,146 (0%) objects (avg size 16 bytes)
    org.objectweb.asm.ClassReader.readConst: 18,304 (99%) bytes in 1,144 (99%) objects
        com.devexperts.aprof.AProfAgent.go: 16,992 (92%) bytes in 1,062 (92%) objects
        com.devexperts.aprof.transformer.AProfTransformer.transform: 1,312 (7%) bytes in 82 (7%) objects
    java.lang.Long.valueOf: 16 (0%) bytes in 1 (0%) objects
        java.lang.Long.valueOf: 16 (100%) bytes in 1 (100%) objects
            com.devexperts.sample.FibonacciNumbers.main: 16 (100%) bytes in 1 (100%) objects
    sun.reflect.UnsafeLongFieldAccessorImpl.get: 16 (0%) bytes in 1 (0%) objects
        com.devexperts.aprof.AProfAgent.go: 16 (100%) bytes in 1 (100%) objects
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Examples

Aforementioned SwingSet2 demo is a complex application, hence its profiling results are not suitable for this tutorial. We will be using a series of specifically designed samples. Some of them make no sense, some are written in non-optimal way, some might even contain bugs. Most likely you will never see them in real applications. However, they help us demonstrate key features of Aprof.

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Code Block
package com.devexperts.sample;
 
public class FibonacciNumbers {
	private static Integer fib(int n) {
		if (n < 2)
			return 1;
		return fib(n - 1) + fib(n - 2);
	}


	public static void main(String[] args) {
		int n = Integer.parseInt(args[0]);
		System.out.printf("fib(%d)=%d\n", n, fib(n));
	}
}

It calculates nth Fibonacci number and prints it to stdout. However, the method returns Integer instead of int which leads to a lot of garbage generated by the program. In large applications it is usually hard to find all such ineffective pieces of code.

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There are no suspicious memory allocations here. Note, that for most many programs it is normal to have the most garbage generated for char[] objects.