public static CancellationToken TokenThatCancelsAfterTwoSeconds(this ConcurrencyLimit runnable)
{
var tokenSource = new CancellationTokenSource();
tokenSource.CancelAfter(TimeSpan.FromSeconds(2));
var token = tokenSource.Token;
return(token);
}
public static async Task SimulateWorkThatTakesOneSecond(this ConcurrencyLimit runnable, int workCount, CancellationToken cancellationToken = default(CancellationToken))
{
Console.WriteLine($"start {workCount}");
try
{
await Task.Delay(1000, cancellationToken);
Console.WriteLine($"done {workCount}");
}
catch (OperationCanceledException)
{
Console.WriteLine($"canceled {workCount}");
}
}
public static void Explain(this ConcurrencyLimit runnable, TextWriter writer)
{
writer.WriteLine(@"
- `SemaphoreSlim` is a handy structure to limit concurrency
- `SemaphoreSlim` does not preserve order
- `SemaphoreSlim` can be used as async lock structure if required (caveat at least 10 times slower than lock)
| Method | Overhead |
|------------------------- |---------:|
| **lock** | 20 ns |
| SemaphoreSlim | 200 ns |
| Semaphore | 1000 ns |
http://www.albahari.com/threading/part2.aspx
");
}
