dc7a9163d9 dc7a9163d9 - 25 days ago 6
C# Question

Limit the number of parallel threads in C#

I am writing a C# program to generate and upload a half million files via FTP. I want to process 4 files in parallel since the machine have 4 cores and the file generating takes much longer time. Is it possible to convert the following Powershell example to C#? Or is there any better framework such as Actor framework in C# (like F# MailboxProcessor)?

Powershell example

$maxConcurrentJobs = 3;

# Read the input and queue it up
$jobInput = get-content .\input.txt
$queue = [System.Collections.Queue]::Synchronized( (New-Object System.Collections.Queue) )
foreach($item in $jobInput)
{
$queue.Enqueue($item)
}

# Function that pops input off the queue and starts a job with it
function RunJobFromQueue
{
if( $queue.Count -gt 0)
{
$j = Start-Job -ScriptBlock {param($x); Get-WinEvent -LogName $x} -ArgumentList $queue.Dequeue()
Register-ObjectEvent -InputObject $j -EventName StateChanged -Action { RunJobFromQueue; Unregister-Event $eventsubscriber.SourceIdentifier; Remove-Job $eventsubscriber.SourceIdentifier } | Out-Null
}
}

# Start up to the max number of concurrent jobs
# Each job will take care of running the rest
for( $i = 0; $i -lt $maxConcurrentJobs; $i++ )
{
RunJobFromQueue
}


Update:

The connection to remote FTP server can be slow so I want to limit the FTP uploading processing.

Answer

Assuming you're building this with the TPL, you can set the ParallelOptions.MaxDegreesOfParallelism to whatever you want it to be.

Parallel.For for a code example.