How to limit the resources used by the system?

Question

I have a loop loop that makes several iterations and has in its scope calculations that require a lot of processing.

The problem is that when executing the code snippet, the use of the processor increases gradually, until locking the application and later the operating system.

Well, my goal is to somehow limit the consumption of those resources that lead to a system crash. I know this will increase response time, but my priority at the moment is not to shut down the system.

The project is in Windows Forms, but this stretch is in a Class Library.

See an excerpt from the code:

private static string[] TodosPossiveis(char[,] letras)
{
            int linhas = letras.GetUpperBound(1) + 1;
            int colunas = letras.GetUpperBound(0) + 1;
            int max = (int)Math.Pow(linhas, colunas);
            string[] todos = new string[max];


            int[] posY = new int[colunas];

            int atual = 0;
            while (atual < max)
            {

                string nova = "";
                for (int i = 0; i < colunas; i++)
                {
                    nova += letras[i, posY[i]];
                }
                for (int i = colunas - 1; i > -1; i--)
                {
                    posY[i]++;
                    if (posY[i] == linhas)
                    {
                        posY[i] = 0;
                    }
                    else
                    {
                        break;
                    }
                }
                todos[atual++] = nova;
            }

            return todos;
 }

This method takes a character set and returns all possible combinations.

I tried to use only primitive variables to improve performance, but even so, when receiving a large set of characters the system ends up crashing.

Answer 1

The first task you should do is to think about whether you have a better way to do this, I doubt you need such a heavy algorithm, or it’s not that heavy. Without a full context it is not helpful and neither is the focus of the question.

Evaluate if you are not having memory problem. Without knowing exactly where the problem is, you will find the wrong solution.

I’ll repeat, the real solution is to profile and find an algorithm, and maybe better data structure.

If you can’t improve it and you’re really getting in the way, then the operating system should be responsible for giving more or less priority to the process.

You can do this by calling the show with start or have your own code decrease priority with the property Process.PriorityClass. A BelowNormal should serve, or may exaggerate and put on Idle.

The estate Process.ProcessorAffinity can help by preventing all colors are used by the process.

There is the possibility of creating some code that minimizes this, but I do not find a good solution in most cases, it is even bigger gambiarra.

Be careful not to do tricks that seem to solve and only get worse.

Answer 2

Using this tutorial you will be able to separate this processing. Will consume the feature of the machine, but will not lock the machine, still via be able to calculate percentage, count processing, etc updating on screen.

Look at this Link

Having some problem in your code just say, we can follow up on another question if that’s the case.

I hope I’ve helped

Answer 3

I know it’s an old post, but it still has some points worth being listed...

1) The heavy memory load and slowness do not surprise, since you are trying to allocate all the possibilities in memory BEFORE returning. If you pass a 10x10 input array, the variable max will be 1E10, or 1 with 10 zeroes in the front. Think that if you try to allocate a return array of this size, it will have at least that amount of byte consumption, which gives a few 9.3 GIGS memory to allocate it all... out of the size of each word itself...

One way around this is to use the operator yield return. See these links:

• What is the use of the reserved word "Yield"?
• https://www.dotnetperls.com/yield
• https://docs.microsoft.com/pt-br/dotnet/csharp/language-reference/keywords/yield

With this, you avoid allocating everything in memory. Another point is to change the return to IEnumerable<string>.

2) In the excerpt nova += letras[i, posY[i]];, instead of using the += operator use a Stringbuilder object - see examples here. At each iteration on this line, the . NET is required to reallocate memory to build the current string.

Answer 4

I worked on a Human Resources Budget system that processed the payroll budget of over 500,000 employees, with several calculation steps that really consumed a lot of operating system resources.

The solution they found was to leave a dedicated machine for the calculation, and they conveniently called it the "Calculating Machine". Thus, the system was separated from the processing of the calculation, and allowed the user to request the execution of the calculation to pick up the results after they were already ready.

Maybe this will work for you too. So, instead of trying to process everything at once and already show the results to the user, just you notify the user that the processing has started and is in progress, and after the processing is completed you notify the user and present the results to him. This can be either on file, report or on a screen of your system.