问题
Hans and I had small discussion recently about the subject and I'm curious how it is really implemented.
See initial talking in the comments here: Are c# timers naturally multithreaded?
回答1:
Staring at the .Net 4.0 reference source, System.Timers.Timer seems to use a System.Threading.Timer to handle the actual implementation details. The latter generates timers by calling AddTimerNative. AddTimerNative is an internal call.
Googling AddTimerNative lead to a lot of interesting results, including Willy Denoyette's comment, where he states that it calls CreateTimerQueueTimer.
That page states that "Callback functions are queued to the thread pool. "
回答2:
Well, I did some investigations... Details are in my blog post
To be short, just summary from there:
- As for SSCLI20 Hans was totally right. There’s really separate thread for handing APCs and queued timers. Thanks for your insistence, btw. I received a chance to dig something interesting :)
- On newer systems it still could be implemented without additional threads. I was just mistakenly assuming it was already there when CLR 2.0 was written. For details see CreateThreadpoolTimer, SetThreadpoolTimer and CloseThreadpoolTimer.
来源：https://stackoverflow.com/questions/6343733/does-clr-internally-spawns-a-thread-to-respond-to-timer-events