GC Benchmark

The code and results below are meant to show the performance differences between Tango and Phobos, isolated to the garbage collector. Benchmark is contributed by Piotr Modzelewski.

Tango code

module bench;

import tango.io.Stdout;


class TreeNode {
    int item;
    TreeNode left, right;

    this(int item, TreeNode left=null, TreeNode right=null) {
        this.item = item;
        this.left = left;
        this.right = right;
    }

    int check() {
        return left is null ? item : item + left.check - right.check;
    }
}

TreeNode makeTree(int item, int depth) {
    if (depth > 0)
        return new TreeNode(item, makeTree(2*item-1, depth-1), makeTree(2*item, depth-1));
    else
        return new TreeNode(item);
}

void main(char[][] args) {
    const minDepth = 4;
    int n = 16; 
    int maxDepth = (minDepth + 2) > n ? minDepth + 2 : n;

    int check = makeTree(0, maxDepth + 1).check;

    auto longLivedTree = makeTree(0, maxDepth);

    for (int depth = minDepth; depth <= maxDepth; depth += 2) {
        int iterations = 1 << (maxDepth - depth + minDepth);
        check = 0;

        for (int i = 1; i <= iterations; i++)
            check += (makeTree(i, depth)).check + (makeTree(-i, depth)).check;
    }

}

Phobos code

module benchphobos;

import std.stdio, std.conv;

class TreeNode {
    int item;
    TreeNode left, right;

    this(int item, TreeNode left=null, TreeNode right=null) {
        this.item = item;
        this.left = left;
        this.right = right;
    }

    int check() {
        return left is null ? item : item + left.check - right.check;
    }
}

TreeNode makeTree(int item, int depth) {
    if (depth > 0)
        return new TreeNode(item, makeTree(2*item-1, depth-1), makeTree(2*item, depth-1));
    else
        return new TreeNode(item);
}

void main(char[][] args) {
    const minDepth = 4;
    int n = 16;
    int maxDepth = (minDepth + 2) > n ? minDepth + 2 : n;

    int check = makeTree(0, maxDepth + 1).check;

    auto longLivedTree = makeTree(0, maxDepth);

    for (int depth = minDepth; depth <= maxDepth; depth += 2) {
        int iterations = 1 << (maxDepth - depth + minDepth);
        check = 0;

        for (int i = 1; i <= iterations; i++)
            check += (makeTree(i, depth)).check + (makeTree(-i, depth)).check;

    }

}

Results

Tango

C:\coding\tangbench>rebuild -O -release -inline -full -cleanup bench.d
C:\coding\tangbench>sh
sh-2.04$ time bench.exe

real    0m14.000s
user    0m0.010s
sys     0m0.010s

Phobos

C:\coding\tangbench>build -release -inline -O -full -cleanup benchphobos.d
C:\coding\tangbench>sh
sh-2.04$ time ./benchphobos.exe

real    0m17.575s
user    0m0.010s
sys     0m0.010s