参考链接
arrival time:the time when a process enters into the ready state and is ready for its execution.(进程进入就绪态的时刻)
burst time: the total time taken by the process for its execution on the CPU（进程在CPU上执行花费的时间，不包括I/O时间）
响应时间（Response time）：Response time is the time spent when the process is in the ready state and gets the CPU for the first time. （自进程就绪至进程第一次获得CPU响应的时间）
Response time = Time at which the process gets the CPU for the first time - Arrival time
周转时间（turnarouad time）：Turnaround time is the total amount of time spent by the process from coming in the ready state for the first time to its completion.（进程从第一次进入就绪状态到完成所花费的总时间。）
Turnaround time = Exit time - Arrival time
等待时间（Waiting time）：Waiting time is the total time spent by the process in the ready state waiting for CPU.（进程处于就绪状态等待CPU所花费的总时间）
Waiting time = Turnaround time - Burst time
例题：Suppose round robin scheduler（时间片轮转调度算法） is used and the quantum is 2. Given the below 4 processes:
hpddy：
响应时间（Response time） : （第一次响应 - 到达时间）
P1: 0 - 0 = 0
P2: 2 - 2 = 0
P3: 6 - 3 = 3
P4: 12 - 9 = 3
周转时间（turnarouad time）: (结束时刻 - 到达时间)
P1: 14 - 0 = 14
P2: 10 - 2 = 8
P3: 8 - 3 = 5
P4: 13 - 9 = 4
等待时间（Waiting time）:（周转时间 - 运行时间）
P1: 14 - 7 = 7
P2: 8 - 4 = 4
P3: 5 - 2 = 3
P4: 4 - 1 = 3
扩展：
带权周转时间 = 周转时间/运行时间