python-3.x - 多数のオブジェクト/プロセスでのpython simpyメモリ使用量

Question

simpy を使用して、非常に多数のオブジェクト (数百万) を持つ DES を作成しています。メモリの問題が発生しており、これに対処する方法を見つけようとしています。どのオブジェクトが他のプロセスとの相互作用をこれ以上受けないかを判断することができるので、理論的にはこれらのオブジェクトをシミュレーションから削除してメモリを解放することができます。以下のテストを作成しました。

import psutil as ps
import simpy
import random


class MemoryUse(object):
    """a class used to output memory usage at various times within the sim"""

    def __init__(self, env, input_dict):

        self.env = env
        self.input_dict = input_dict

        self.env.process(self.before())
        self.env.process(self.during())
        self.env.process(self.after_sr())
        self.env.process(self.after())

    def before(self):

        yield self.env.timeout(0)
        print("full object list and memory events at time: ", self.env.now, " ", ps.virtual_memory())
        print(len(self.input_dict), len(self.env._queue))

    def during(self):
        yield self.env.timeout(2)
        print("full object list and events ar time: ", self.env.now, " ", ps.virtual_memory())
        print(len(self.input_dict), len(self.env._queue))

    def after_sr(self):

        yield self.env.timeout(4)
        print("reduced object list and reduced events at time: ", self.env.now, " ", ps.virtual_memory())
        print(len(self.input_dict), len(self.env._queue))

    def after(self):
        yield self.env.timeout(6)
        print("no objects and no events at time: ", self.env.now, " ", ps.virtual_memory())
        print(len(self.input_dict), len(self.env._queue))


class ExObj(object):
    """a generic object"""

    def __init__(self, env, id, input_dict):

        self.env = env
        self.id = id
        self.input_dict = input_dict

        if random.randint(0, 100) < 70:
            # set as SR
            self.timeout = 2
        else:
            self.timeout = 4

    def action(self):

        yield self.env.timeout(self.timeout)

        del self.input_dict[self.id]


class StartObj(object):
    """this enables me to create the obj events after the sim has started so as to measure memory usage before the events
    associated with the object exists"""

    def __init__(self, env, input_dict):

        self.env = env
        self.input_dict = input_dict

        self.env.process(self.start_obj())

    def start_obj(self):

        yield self.env.timeout(1)

        for k, v in self.input_dict.items():
            self.env.process(v.action())

        yield self.env.timeout(0)

# memory usage before we do anything
print("before all: ", ps.virtual_memory())

# create simpy env
env = simpy.Environment()
obj_dict = {}

# create memory calculation events
memory = MemoryUse(env, obj_dict)

# create objects
for i in range(2500000):
    obj_dict[i] = ExObj(env, i, obj_dict)


# create process that will itself start events associated with the objects
start = StartObj(env, obj_dict)

# run
env.run()

# clear the dict if not already clear
for j in range(2500000):
    obj_dict.clear()

# final memory check
print("after all: ", ps.virtual_memory())
print(len(obj_dict))

多くのオブジェクトが削除され、プロセスが完了したため (約 70%)、時間 4 までにメモリ使用量が低下すると予想していました。ただし、メモリ使用量は同じままのようです (以下を参照)。これはなぜですか？このメモリは何に使われていますか？完了したプロセスはシミュレーションに残りますか?

before all:  svmem(total=42195423232, available=39684155392, percent=6.0, used=2246373376, free=38884859904, active=2390749184, inactive=441712640, buffers=263155712, cached=801034240, shared=28721152)
full object list and memory events at time:  0   svmem(total=42195423232, available=38834251776, percent=8.0, used=3096276992, free=38035181568, active=3241959424, inactive=441466880, buffers=263159808, cached=800804864, shared=28721152)
2500000 4
full object list and events ar time:  2   svmem(total=42195423232, available=35121584128, percent=16.8, used=6808891392, free=34322219008, active=6947561472, inactive=441761792, buffers=263163904, cached=801148928, shared=28774400)
2500000 2500002
reduced object list and reduced events at time:  4   svmem(total=42195423232, available=35120973824, percent=16.8, used=6809530368, free=34321600512, active=6948368384, inactive=441737216, buffers=263168000, cached=801124352, shared=28745728)
767416 767417
no objects and no events at time:  6   svmem(total=42195423232, available=38448134144, percent=8.9, used=3482365952, free=37648760832, active=3627053056, inactive=441733120, buffers=263172096, cached=801124352, shared=28745728)
0 0
after all:  svmem(total=42195423232, available=38825793536, percent=8.0, used=3104706560, free=38026420224, active=3250180096, inactive=441733120, buffers=263172096, cached=801124352, shared=28745728)
0

Process finished with exit code 0