public unsafe MemoryAccessBenchmark()
{
// Create a memory mapped file and fill it with random bytes
_memory = new MemoryMappedFileMemory(ItemLength * ItemCount);
GenerateRandomBytes(_memory.DataPointer, _memory.Length);
_readOnlyBuffer = _memory.CreateReadOnlyBuffer();
// Create the same RNG for both benchmarks
_random = XorShiftRandom.Create(0x6780867534);
// Allocate 5 bytes for the
_constantMemoryPointer = Marshal.AllocHGlobal(5);
}
private static unsafe void GenerateRandomBytes(byte *pointer, long count)
{
// Forget about alignment since this test will run on x64
ulong *p = (ulong *)pointer;
long c = count >> 3;
var random = XorShiftRandom.Create(0x2985194649313);
for (int i = 0; i < c; i++)
{
*p++ = random.Next();
}
int remainingBytes = (int)(count & 0x7);
if (remainingBytes > 0)
{
ulong n = random.Next();
new Span <byte>(&n, remainingBytes).CopyTo(new Span <byte>(p, remainingBytes));
}
}