Code:

<code d>
import std.stdio;
import std.datetime;

ubyte[] alloc_test(size_t size)
{
    auto starttime = Clock.currTime();
    ubyte[] arr = new ubyte[size];
    auto duration = Clock.currTime() - starttime;
    writeln("size ", size, ", time: ", duration);
    return arr;
}

int main(string[] args)
{
    size_t size = 1u;
    for (;;)
    {
        alloc_test(size);
        size *= 10u;
    }
    return 0;
}
</code>

Output:

<code>
$ ./alloc
size 1, time: 22 μs and 3 hnsecs
size 10, time: 3 μs
size 100, time: 2 μs
size 1000, time: 10 μs and 6 hnsecs
size 10000, time: 539 μs and 7 hnsecs
size 100000, time: 195 μs and 5 hnsecs
size 1000000, time: 1 ms, 506 μs, and 6 hnsecs
size 10000000, time: 15 ms, 566 μs, and 5 hnsecs
size 100000000, time: 43 ms, 450 μs, and 9 hnsecs
size 1000000000, time: 268 ms, 474 μs, and 2 hnsecs
core.exception.OutOfMemoryError@../../../../src/libphobos/libdruntime/core/exception.d(705): Memory allocation failed
----------------
</code>