INTQ --Threading, C#

Explain SpinLock, SpinWait? vs lock
sl.enter/exit while(!flag {sw.Spin(100);}

Explain how Memory Barrier works?
Thread.MemoryBarrier(), Caching Optimization can move instruction around

What is Re-entrant?

How Semaphore works?
SemaphoreSlimw= new (3);_sm.Wait(); block after 3 entrer; sm.Release();

Explain InterLock.Increment/Decrement for 64-bit on 32-bit environment?
need two separate instrument InterLock.Increment(ref i);

How to use Cancellaton Token in Task?
CancelationTokenSource src. src.Token pass in

What are SynchronizationContext?
Send/Post, Dispatcher, WF/ASPNet

How do you use BlockingCollection?

How the exception in Thread handled?
WPF/WF App.DispatcherUnhandledExpcetion/ThreadExcetion UI Thread
AppDomain.Current.UnhandledException
General --Process Shutdown, Calling thread will not see it.

How to use TaskCompletionSource?
StateMachine, Task  workflow, tcs.Task ReadOnly, tcs.SetResult/Cancel/Exception

How to use Parallel.For ?
Parallel.For(1,100,Action<int>)

why Binary search is O(logn)?


What is Volatile, [Thread Static] and Thread Local?
access by all thread, not optimize, each static field has its own copy, each thread has its own.

Is Lazy thread safe ?
set by 1st thread, if IsThreadSafe=true;

What is Priority Inversion?
L hold up H due to resource lock, M comes in unblocked so M>L, make L temporarity High to exec, release H

what is Thread Stavation ?
L cannot do much since H occupy.

Explain how Monitor.Pulse/Wait work?
Pulse signal to get on ReadyQueue, Wait to sit on waitQueue. vs. Enter/Exit

How to setup BeginInvoke/EndInvoke for Action?
Action a; a.BeginInvoke(new AsyncCallback(cb_f,a));
void (cb_f(IAsyncResult ar) { Action a=ar.AsyncState as Action; a.EndInvoke();}

Explain Dinning Philosopher Problem? (Minitor, Executor, Manager)

What is Mutex?
Mutex.TryOpenExisting("Name", out m); m.WaitOne(); m.ReleaseMutex();

What is Multi-cast Delegate?
D d1,d2; MuticastDelegate mcd=D.Combine(d1,d2);

How much does it cost to set up a thread?
200K CPU cycle, 1M Stack,64 bit 6 Kernal Pages, 2K cycle for Context Switching.

Explain GC and WeakReference
Reachable -- strong ref, Unreachable/FinalizerQueue =long/short weakref, 2-phase GC.
WeakReference wObj= new(TrackResurrection=true); wObj.Target is strongRef but check null needed.

What is an example of a Closure?
Func f=delegate { int i=5; i=outside var; return 5;}

Explain Syntax for Enumerable.Aggragate((acc,i)=>acc+i)

Explain UML notations of Realization/Inheritance/Aggragation/Composition/Association

Explain Design Pattern Visitor/Singleton/

What is Rx CombineLastest?