postgraduate-prep/experiment/code/priority.py

104 lines
3.7 KiB
Python

#!/usr/bin/env python3
"""
优先级调度算法 (Priority)
支持 IO 模拟
"""
from typing import List, Dict
import heapq
from base import (
Process,
ProcessScheduler,
generate_random_processes,
print_processes
)
class PriorityScheduler(ProcessScheduler):
"""优先级调度 (数值越小优先级越高)
支持 IO 模拟
"""
def __init__(self, processes: List[Process], preemptive: bool = False):
super().__init__(processes)
self.preemptive = preemptive
def schedule(self) -> Dict:
"""优先级调度算法 (支持IO模拟)"""
all_processes = list(self.processes)
for p in all_processes:
self.init_process(p, p.arrival_time)
events = []
for p in all_processes:
heapq.heappush(events, (p.arrival_time, 'arrival', id(p), p))
ready_queue = [] # (priority, pid, process)
completed = []
current_time = 0
while len(completed) < len(all_processes):
while events and events[0][0] <= current_time:
event_time, event_type, uid, p = heapq.heappop(events)
if event_type == 'arrival':
p.status = self.STATUS_READY
heapq.heappush(ready_queue, (p.priority, id(p), p))
elif event_type == 'io_complete':
if p.status == self.STATUS_IO_WAIT:
p.status = self.STATUS_READY
heapq.heappush(ready_queue, (p.priority, id(p), p))
if not ready_queue:
if events:
current_time = events[0][0]
continue
else:
break
_, _, current_process = heapq.heappop(ready_queue)
if current_process.start_time == -1:
current_process.start_time = current_time
current_process.status = self.STATUS_RUNNING
if current_process.current_cpu_idx < len(current_process.cpu_bursts):
cpu_burst = current_process.cpu_bursts[current_process.current_cpu_idx]
self.gantt_chart.append((current_time, current_process.pid, 'CPU', cpu_burst))
current_time += cpu_burst
current_process.remaining_cpu_time -= cpu_burst
current_process.current_cpu_idx += 1
io_idx = current_process.current_cpu_idx - 1
if io_idx < len(current_process.io_bursts):
io_time = current_process.io_bursts[io_idx]
current_process.status = self.STATUS_IO_WAIT
heapq.heappush(events, (current_time + io_time, 'io_complete', id(current_process), current_process))
else:
current_process.status = self.STATUS_TERMINATED
current_process.completion_time = current_time
self.calculate_metrics(current_process, current_time)
completed.append(current_process)
else:
current_process.status = self.STATUS_TERMINATED
current_process.completion_time = current_time
self.calculate_metrics(current_process, current_time)
completed.append(current_process)
self.results = completed
return self.print_results("Priority (优先级调度)")
if __name__ == "__main__":
processes = generate_random_processes(n=5, seed=42, io_probability=0.5)
print_processes(processes, "测试数据")
scheduler = PriorityScheduler(processes)
scheduler.schedule()