CODEWITHSUNDEEP
c#asynchronoustaskprocess.start
sbmobile
sbmobile

Reputation: 95

c# running multiple process.Start() asynchronously

I have a folder containing multiple PCL files which need converting to PDF. I am able to achieve this using a third party exe. To speed this up I am trying to run multiple Tasks(), each which starts a new System.Diagnostics.Process using the exe;

System.Diagnostics.Process process = new System.Diagnostics.Process();
            process.StartInfo.FileName = $@".\WinPCLtoPDF\WinPCLtoPDF.exe";
            process.StartInfo.Arguments = $@"{StepParameters["StagingFileName"]} {StepParameters["StagingFileName"]}.pdf batch";
            process.Start();
            process.WaitForExit();

The tasks are added to a List<Task> and each is awaited before the program exits.

            foreach (FileInfo fileInfo in files)
            {
                tasks.Add(ProcessDocumentTaskAsync(batchType, fileInfo, deleteOriginalFile));

                while (tasks.Count < files.Count() && tasks.Where(x => !x.IsCompleted).Count() > concurrentTasks)
                {
                    Thread.Sleep(50);
                }
            }

The Tasks are created using a method like this.

        private async static Task ProcessDocumentTaskAsync(BatchType batchType, FileInfo fileInfo, bool deleteOriginalFile)
        {
            await Task.Run(() =>
            {   
                ProcessParameters processParameters = ProcessParams();/////get process params            
                DocumentProcessor documentProcessor = GetDocumentProcessor(batchType, processParameters);
                using (documentProcessor)
                {
                    documentProcessor.ProcessDocument();
                }
            });
        }

This pattern works for other tasks and you can see from a log file that jobs are being performed asynchronously. However, with this WinPCLtoPDF.exe, it appears to only process one file at a time, yet the task manager shows there are multiple processes running. Process 1 & 2 for example will wait, while 3 starts and finishes and is replaced by 4, 5 etc, until finally the whole folder is process and 1 then 2 complete.

Can I find out why 1 & 2 are appear to be being blocked and do not complete quickly, allowing other tasks to start?

Upvotes: 1

Views: 4597

Answers (1)

gpro
gpro

Reputation: 592

The easiest solution is probably (as mentioned in a comment) to use Parallel.ForEach. In your case it would look something like:

        Parallel.ForEach(files, new ParallelOptions() { MaxDegreeOfParallelism = Environment.ProcessorCount }, fileInfo =>
        {
            ProcessParameters processParameters = ProcessParams();/////get process params            
            DocumentProcessor documentProcessor = GetDocumentProcessor(batchType, processParameters);
            using (documentProcessor)
            {
                documentProcessor.ProcessDocument();
            }
        });

Note on your trying:

The reason it is not running all the Tasks at once is probably because you are awaiting the Task completion in your ProcessDocumentTaskAsync function.

Upvotes: 0

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