Abstract
- Coordination of execution of multiple Process (进程) or Thread in a system to ensure that they access shared resources in a controlled and predictable manner
- We can use tools like
Terminologies
Busy Waiting (忙等待)
- Also known as Spinning
- CPU is involved to keep check for the state
- A Process (进程)/Thread repeatedly checks a condition without sleeping or giving up the processor until the condition is satisfied
- This is in contrast to waiting for a condition using a mechanism such as a Semaphore (信号量) or a Mutex (互斥体), which releases the processor and allows other threads to run while waiting for the condition to be met
Benefits
- Simple and efficient synchronization mechanism
- Shines when condition is expected to be met very quickly. Like Process (进程) waiting for input from the keyboard
Cons
- Can waste CPU resources if the condition is not met quickly, especially on Multi-core Chip, generally considered to be a bad practice for most applications