128 GB Ram x64 cpu上的内存不足问题

Question

I am working on a program where it reads a 312 MB encrypted file into memory stream , decrypts it and copies into destination stream. My program works well with file size of around 120 MB . I couldn't figure out why it is failing for this ?

My System info : 64 bit cpu , RAM : 128 GB Also the c# code I built on using Any CPU setting in Configuration Manager.

I wrote a sample program to check where I am getting out of memory and I see that its failing at 512 MB. I do know that the Memory stream requires contigous blocks in the Memory as the RAM is fragmented. But the RAM size is huge here, I tried in multiple machines as well with RAMs of 14 GB, 64GB & 8GB.

Any help is appreciated.

The sample program I wrote to test the Out of Memory Size :

 const int bufferSize = 4096;
            byte[] buffer = new byte[bufferSize];

            int fileSize = 1000 * 1024 * 1024;

            int total = 0;

            try
            {
                using (MemoryStream memory = new MemoryStream())
                {
                    while (total < fileSize)
                    {
                        memory.Write(buffer, 0, bufferSize);
                        total += bufferSize;
                    }

                }

                Console.WriteLine("No errors");

            }
            catch (OutOfMemoryException)
            {
                Console.WriteLine("OutOfMemory around size : " + (total / (1024m * 1024.0m)) + "MB");
            }

Answer 1

Just running out of Large Object Heap I guess. However another approach to solving your problem is to not read the stream into memory - most decrypt algorithms just want a System.IO.Stream - reading it into memory seems a relatively pointless step - just pass the decrypt api your incoming file or network stream instead.

Answer 2

Try disabling the option "Prefer 32 bits" from the project's properties, in "Build" tab, thats works for me. Good luck!