Dealing With Contention easy
What is 'Busy Waiting' (Spinning)?
- A When a thread is doing heavy math.
- B When a thread yields the CPU while waiting.
- C A thread sits in a loop checking a condition (`while(!lock) {}`) constantly consuming CPU cycles instead of sleeping.
- D When the network is busy.
Answer: C. A thread sits in a loop checking a condition (`while(!lock) {}`) constantly consuming CPU cycles instead of sleeping.
Spinlocks are useful for *very short* waits (nanoseconds) to avoid context switch cost, but waste energy if held long.
One system design question a day, with spaced repetition so the ones you miss come back.
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