下面显示了我的代码，它模拟了具有两种到达类型的M/M/1抢占队列，其中第一种类型的优先级高于第二种类型。然而，我不知道为什么在我的代码中，抢先规则没有按照它应该的方式工作。我的意思是，在抢占队列中，例如，如果类型2的作业正在接收服务，并且类型1的作业到达，则服务器中断类型2作业的服务并开始类型1作业的服务。但是，完成类型1作业的服务后，应继续中断的类型2作业的服务。
在我的代码中，如果作业类型2正在接收服务，并且作业类型1到达，则作业类型2立即永久离开系统。我想知道你能不能告诉我为什么会发生这种情况，以及我该如何解决？
真的很感激你提前花时间和精力。
import random
import simpy
rn_seed = 10
t1_interval_arrivals = 20.0
t2_interval_arrivals = 1
t1_interval_service = 5
t2_interval_service = 20
def type_1_generator(env, interval, server):
i = 0
while True:
c = job(env, "type_1"+" #"+ str(i), "type_1", server, t1_interval_service)
env.process(c)
t = random.expovariate(1.0 / interval)
yield env.timeout(t)
i +=1
def type_2_generator(env, interval, server):
i = 0
while True:
c = job(env, "type_2"+" #"+str(i), "type_2", server, t2_interval_service)
env.process(c)
t = random.expovariate(1.0 / interval)
yield env.timeout(t)
i +=1
def job(env, name, typ , server, sr_interval):
arrive = env.now
print("Job", name, "Arrived at: ",arrive)
service_interval = random.expovariate(1.0 / sr_interval)
print("Job", name, "Service time: ",service_interval)
if typ == "type_1":
while service_interval:
with server.request(priority=1) as req:
yield req
yield env.timeout(service_interval)
service_interval = 0
print("Job", name, "Left system at: ",env.now)
elif typ == "type_2":
while service_interval:
try:
start = env.now
with server.request(priority=2) as req:
yield req
yield env.timeout(service_interval)
service_interval = 0
print("Job", name, "Left system at: ",env.now)
except simpy.Interrupt:
print("Job", name, "Is interrupted at: ",env.now)
service_interval -= env.now - start
print("Job", name, "Remaining service: ",env.now)
print("Job", name, "Left system at ",env.now)
# Setup and start the simulation
random.seed(rn_seed)
env = simpy.Environment()
# Start processes and run
server = simpy.PreemptiveResource(env, capacity=1)
env.process(type_1_generator(env, t1_interval_arrivals, server))
env.process(type_2_generator(env, t2_interval_arrivals, server))
env.run()
以下是结果示例：
Job type_2 #1 Arrived at: 0.5601717881563535
Job type_2 #1 Service time: 34.69876113045603
Job type_1 #1 Arrived at: 16.94474499667717
Job type_1 #1 Service time: 0.22635015810062187
Job type_2 #1 Is interrupted at: 16.94474499667717
Job type_2 #1 Remaining service: 18.31418792193521
Job type_2 #1 Left system at 16.94474499667717
Job type_1 #1 Left system at: 17.17109515477779
在上面的结果中，你可以看到；作业类型1#1"；到达16.94时，服务器中断了"0"的服务；作业类型2#1"；并且该作业的剩余服务时间是18.31。然而，一旦服务器完成了"；作业类型1#1"；它从不继续为"0"提供服务；作业类型_2#1"；。事实上；作业类型2#1"；立即离开系统；作业类型1#1"；到达。这清楚地表明了我的代码有什么问题。为什么"作业类型2#1"；是否立即离开系统，而服务器从未继续为此作业提供服务？
我对您的代码做了一些更改。需要注意的是，当您重新提交资源请求时，它会被放在队列的末尾。因此，我给中断的第二类工作比新的第二类型工作优先级更高。第一类作业仍然具有最高优先级。我还添加了一些打印报表。
import random
import simpy
rn_seed = 10
t1_interval_arrivals = 20.0
t2_interval_arrivals = 1
t1_interval_service = 5
t2_interval_service = 20
# use for unique id across all jobs
i = 0
def type_1_generator(env, interval, server):
global i
while i < 6:
c = job(env, "type_1"+" #"+ str(i), "type_1", server, t1_interval_service)
i +=1
env.process(c)
t = random.expovariate(1.0 / interval)
yield env.timeout(t)
def type_2_generator(env, interval, server):
global i
while i < 4:
c = job(env, "type_2"+" #"+str(i), "type_2", server, t2_interval_service)
i +=1
env.process(c)
t = random.expovariate(1.0 / interval)
yield env.timeout(t)
def job(env, name, typ , server, sr_interval):
"""
use three priorites so interuped jobs can
take precendence over type 2 jobs that have
not started yet
job priorities are:
type 1: 1
type 2: 3
interupted type 2: 2
"""
arrive = env.now
print("Job", name, "Arrived at: ",arrive)
service_interval = random.expovariate(1.0 / sr_interval)
print("Job", name, "Service time: ",service_interval)
if typ == "type_1":
while service_interval:
with server.request(priority=1) as req:
yield req
print("Job", name, "seized resource at: ",env.now)
yield env.timeout(service_interval)
service_interval = 0
print("Job", name, "released resource at: ",env.now)
print("Job", name, "finished at: ",env.now)
elif typ == "type_2":
priority=3
while service_interval:
try:
with server.request(priority=priority) as req:
yield req
start = env.now
if priority == 3:
print("Job", name, "seized resource at: ",env.now)
else:
print("Job", name, "resumed with resource at: ",env.now)
yield env.timeout(service_interval)
service_interval = 0
print("Job", name, "released resource at: ",env.now)
except simpy.Interrupt:
# up priority to take precenance of not started jobs
priority=2
print("Job", name, "Is interrupted at: ",env.now)
service_interval -= env.now - start
print("Job", name, "Remaining service: ",service_interval)
print("Job", name, "finished ",env.now)
# Setup and start the simulation
random.seed(rn_seed)
env = simpy.Environment()
# Start processes and run
server = simpy.PreemptiveResource(env, capacity=1)
env.process(type_1_generator(env, t1_interval_arrivals, server))
env.process(type_2_generator(env, t2_interval_arrivals, server))
env.run()