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POArrays sort vs parallelSort performance comparision
 

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  1. POArrays sort vs parallelSort performance comparision
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    <h2><strong>I've downloaded <code>java8-ea</code> release and did a fast comparison between <code>Array.sort</code> and <code>Arrays.parallelSort</code>.</strong></h2> <p>And this was the result: <img src="https://i.stack.imgur.com/x3088.jpg" alt="enter image description here"></p> <p>I can understand that the praralleSort should perform at least as Plain old <code>sort</code>, if not faster.. but this is not what happened.</p> <h2><strong>The Comparison done on the following specs:</strong></h2> <p>HP ProBook <code>Intel Core i5</code> with <code>4G RAM</code> on <code>Ubuntu 13.04 Linux</code> with JDK of version: <code>Java HotSpot(TM) 64-Bit Server VM (build 25.0-b23, mixed mode)</code></p> <h3><strong>I've created an array of Custom object of three fields by this way (add object in reserve order):</strong></h3> <pre><code>package com.cmd; import java.util.Arrays; public class Main { public static void main(String[] args) { for (int i=100; i &lt;= 10_000_000; i*=10){ runTest(i); } } private static void runTest(final int size){ // Fist obtain two Arrays of same data Employee[] empArrForSort = createVeryLargeEmpArray(size); Employee[] empArrForSortCopy = Arrays.copyOf(empArrForSort, empArrForSort.length); long start = System.currentTimeMillis(); Arrays.sort(empArrForSort, (e1, e2) -&gt; new Integer(e1.getId()).compareTo(e2.getId())); logStart(size + ": sort", start); start = System.currentTimeMillis(); Arrays.parallelSort(empArrForSortCopy, (e1, e2) -&gt; new Integer(e1.getId()).compareTo(e2.getId())); logStart(size + ": parallel sort", start); } private static void logStart(String label, long startTimeMillis) { System.out.println("End " + label + " the array. It took: " + (System.currentTimeMillis() - startTimeMillis) + " ms"); } private static Employee[] createVeryLargeEmpArray(final int size) { Employee[] ret = new Employee[size]; for (int i = 0; i &lt; ret.length; i++) { ret[i] = Employee.createEmployee(ret.length - i, "Mohammad" + i, ""); } return ret; } static class Employee { private int id; private String name; private String email; private Employee(int id, String name, String email) { this.id = id; this.name = name; this.email = email; } public static Employee createEmployee(int id, String name, String email) { return new Employee(id, name, email); } public int getId() { return id; } } } </code></pre> <p>And, Another run shows that, Parallel only perform pad when the list contains 10,000,000, in all other cases it looks better. </p> <pre><code>&gt;java -Xmx2000m com.cmd.Main End 100: sort the array. It took: 110 ms End 100: parallel sort the array. It took: 6 ms End 1000: sort the array. It took: 2 ms End 1000: parallel sort the array. It took: 3 ms End 10000: sort the array. It took: 11 ms End 10000: parallel sort the array. It took: 11 ms End 100000: sort the array. It took: 15 ms End 100000: parallel sort the array. It took: 37 ms End 1000000: sort the array. It took: 553 ms End 1000000: parallel sort the array. It took: 187 ms End 10000000: sort the array. It took: 640 ms End 10000000: parallel sort the array. It took: 1099 ms </code></pre>
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    1. PTQuestion
    1. USMuhammad Hewedy
    1. USMuhammad Hewedy
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    1. PO
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    1. This table or related slice is empty.
    1. COAnd what is your question?
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      1. POArrays sort vs parallelSort performance comparision
      1. USmschenk74
    2. COHow many cores do you have in your system?
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      1. POArrays sort vs parallelSort performance comparision
      1. USEdwin Dalorzo
    3. COI am not sure, but I have a Intel Core i5 second Gen.
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      1. POArrays sort vs parallelSort performance comparision
      1. USMuhammad Hewedy
 

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