What thread does Timer use wile waiting?

Asked Feb 22 '18 at 15:04

Active Feb 22 '18 at 15:04

Viewed 47 times

In MS book for certification I see this part:

public Task SleepAsyncA(int millisecondsTimeout)
{
    return Task.Run(() => Thread.Sleep(millisecondsTimeout));
}
public Task SleepAsyncB(int millisecondsTimeout)
{
    TaskCompletionSource<bool> tcs = null;
    var t = new Timer(delegate { tcs.TrySetResult(true); }, null, -1, -1);
    tcs = new TaskCompletionSource<bool>(t);
    t.Change(millisecondsTimeout, -1);
    return tcs.Task;
}

The SleepAsyncA method uses a thread from the thread pool while sleeping. The second method, however, which has a completely different implementation, does not occupy a thread while waiting for the timer to run. The second method gives you scalability.

But, does not Timer uses dedicated thread while waiting particular amount of time?

asked Feb 22 '18 at 15:04

Alexey Klipilin

1,866
13
29

What kind of timer is it? See https://stackoverflow.com/a/6339682/43846 – stuartd Feb 22 '18 at 15:07
2

Yes it does. It is however a thread that handles all active timers. So it is "scalable". You can see it when you enable unmanaged debugging, shows up as "clr.dll!ThreadPoolMgr::TimerThreadStart". Do favor Task.Delay() instead of hoofing it yourself. – Hans Passant Feb 22 '18 at 15:21
@HansPassant, Ok, so, it's because one thread for managing all timers, thanks! – Alexey Klipilin Feb 22 '18 at 15:28
@stuartd, this is Threading Timer yes – Alexey Klipilin Feb 22 '18 at 15:38

What thread does Timer use wile waiting?

0 Answers0