move all class attributes to __init__

experiments/simbricks/exectools.py

@@ -27,6 +27,7 @@ import re
 import shlex
 import shutil
 import signal
+import typing as tp
 from asyncio.subprocess import Process
 
 
@@ -45,8 +46,6 @@ class HostConfig(object):
 
 
 class Component(object):
-    proc: Process
-    terminate_future: asyncio.Task[int]
 
     def __init__(self, cmd_parts, with_stdin=False):
         self.is_ready = False
@@ -58,6 +57,9 @@ class Component(object):
         #print(cmd_parts)
         self.with_stdin = with_stdin
 
+        self._proc: tp.Optional[Process] = None
+        self._terminate_future: tp.Optional[asyncio.Task[int]] = None
+
     def _parse_buf(self, buf, data):
         if data is not None:
             buf.extend(data)
@@ -100,19 +102,19 @@ class Component(object):
     async def _waiter(self):
         out_handlers = asyncio.ensure_future(
             asyncio.wait([
-                self._read_stream(self.proc.stdout, self._consume_out),
-                self._read_stream(self.proc.stderr, self._consume_err)
+                self._read_stream(self._proc.stdout, self._consume_out),
+                self._read_stream(self._proc.stderr, self._consume_err)
             ])
         )
-        rc = await self.proc.wait()
+        rc = await self._proc.wait()
         await out_handlers
         await self.terminated(rc)
         return rc
 
     async def send_input(self, bs, eof=False):
-        self.proc.stdin.write(bs)
+        self._proc.stdin.write(bs)
         if eof:
-            self.proc.stdin.close()
+            self._proc.stdin.close()
 
     async def start(self):
         if self.with_stdin:
@@ -120,38 +122,38 @@ class Component(object):
         else:
             stdin = None
 
-        self.proc = await asyncio.create_subprocess_exec(
+        self._proc = await asyncio.create_subprocess_exec(
             *self.cmd_parts,
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE,
             stdin=stdin,
         )
-        self.terminate_future = asyncio.ensure_future(self._waiter())
+        self._terminate_future = asyncio.ensure_future(self._waiter())
         await self.started()
 
     async def wait(self):
-        await self.terminate_future
+        await self._terminate_future
 
     async def interrupt(self):
-        if self.terminate_future.done():
+        if self._terminate_future.done():
             return
-        self.proc.send_signal(signal.SIGINT)
+        self._proc.send_signal(signal.SIGINT)
 
     async def terminate(self):
-        if self.terminate_future.done():
+        if self._terminate_future.done():
             return
-        self.proc.terminate()
+        self._proc.terminate()
 
     async def kill(self):
-        self.proc.kill()
+        self._proc.kill()
 
     async def int_term_kill(self, delay=5):
         await self.interrupt()
-        _, pending = await asyncio.wait([self.terminate_future], timeout=delay)
+        _, pending = await asyncio.wait([self._terminate_future], timeout=delay)
         if len(pending) != 0:
             print('terminating')
             await self.terminate()
-            _,pending = await asyncio.wait([self.terminate_future],
+            _,pending = await asyncio.wait([self._terminate_future],
                     timeout=delay)
             if len(pending) != 0:
                 print('killing')
@@ -199,7 +201,6 @@ class SimpleComponent(Component):
 
 
 class SimpleRemoteComponent(SimpleComponent):
-    pid_fut: asyncio.Future
 
     def __init__(
         self,
@@ -231,8 +232,11 @@ class SimpleRemoteComponent(SimpleComponent):
 
         # wrap up command in ssh invocation
         parts = self._ssh_cmd(remote_parts)
+
         super().__init__(label, parts, *args, **kwargs)
 
+        self._pid_fut: tp.Optional[asyncio.Future] = None
+
     def _ssh_cmd(self, parts):
         """SSH invocation of command for this host."""
         return [
@@ -245,34 +249,34 @@ class SimpleRemoteComponent(SimpleComponent):
 
     async def start(self):
         """Start this command (includes waiting for its pid."""
-        self.pid_fut = asyncio.get_running_loop().create_future()
+        self._pid_fut = asyncio.get_running_loop().create_future()
         await super().start()
-        await self.pid_fut
+        await self._pid_fut
 
     async def process_out(self, lines, eof):
         """Scans output and set PID future once PID line found."""
-        if not self.pid_fut.done():
+        if not self._pid_fut.done():
             newlines = []
             pid_re = re.compile(r'^PID\s+(\d+)\s*$')
             for l in lines:
                 m = pid_re.match(l)
                 if m:
                     pid = int(m.group(1))
-                    self.pid_fut.set_result(pid)
+                    self._pid_fut.set_result(pid)
                 else:
                     newlines.append(l)
             lines = newlines
 
-            if eof and not self.pid_fut.done():
+            if eof and not self._pid_fut.done():
                 # cancel PID future if it's not going to happen
                 print('PID not found but EOF already found:', self.label)
-                self.pid_fut.cancel()
+                self._pid_fut.cancel()
         await super().process_out(lines, eof)
 
     async def _kill_cmd(self, sig):
         """Send signal to command by running ssh kill -$sig $PID."""
         cmd_parts = self._ssh_cmd([
-            'kill', '-' + sig, str(self.pid_fut.result())
+            'kill', '-' + sig, str(self._pid_fut.result())
         ])
         proc = await asyncio.create_subprocess_exec(*cmd_parts)
         await proc.wait()
@@ -288,7 +292,9 @@ class SimpleRemoteComponent(SimpleComponent):
 
 
 class Executor(object):
-    ip = None
+
+    def __init__(self):
+        self.ip = None
 
     def create_component(self, label, parts, **kwargs) -> SimpleComponent:
         raise NotImplementedError('Please Implement this method')
@@ -354,6 +360,8 @@ class LocalExecutor(Executor):
 class RemoteExecutor(Executor):
 
     def __init__(self, host_name, workdir):
+        super().__init__()
+
         self.host_name = host_name
         self.cwd = workdir
         self.ssh_extra_args = []

experiments/simbricks/experiments.py

@@ -29,7 +29,7 @@ import typing as tp
 from simbricks.exectools import Executor, SimpleComponent
 from simbricks.experiment.experiment_environment import ExpEnv
 from simbricks.experiment.experiment_output import ExpOutput
-from simbricks.proxy import NetProxyConnecter, NetProxyListener, SimProxy
+from simbricks.proxy import NetProxyConnecter, NetProxyListener
 from simbricks.simulators import (
     HostSim, I40eMultiNIC, NetSim, NICSim, PCIDevSim, Simulator
 )
@@ -43,27 +43,29 @@ class Experiment(object):
     Holds information about the simulators to run and paramaters to configure
     the experiment.
     """
-    name: str
-    """This experiment's name. Can be used to filter multiple experiments to be
-    run."""
-    timeout: int
+
+    def __init__(self, name: str, timeout: int = 0):
+        self.name = name
+        """
+        This experiment's name. Can be used to filter multiple experiments to be
+        run.
+        """
+        self.timeout = timeout
         """Timeout for experiment in seconds."""
-    checkpoint = False
+        self.checkpoint = False
         """Whether to use checkpoints in experiment.
 
         Can for example be used to speed up booting a host simulator by first
-    running in a less accurate mode. Before we then start the application we are
-    interested in, a checkpoint is taken and the simulator shut down. Then, the
-    simulator is restored in the accurate mode using this checkpoint."""
-    no_simbricks = False
+        running in a less accurate mode. Before we then start the application we
+        are interested in, a checkpoint is taken and the simulator shut down.
+        Then, the simulator is restored in the accurate mode using this
+        checkpoint."""
+        self.no_simbricks = False
         """`true` - No simbricks adapters are used in the simulators."""
-    hosts: tp.List[HostSim] = []
-    pcidevs: tp.List[PCIDevSim] = []
-    networks: tp.List[NetSim] = []
-    metadata = {}
-
-    def __init__(self, name: str):
-        self.name = name
+        self.hosts: tp.List[HostSim] = []
+        self.pcidevs: tp.List[PCIDevSim] = []
+        self.networks: tp.List[NetSim] = []
+        self.metadata = {}
 
     def add_host(self, sim: HostSim):
         for h in self.hosts:
@@ -108,25 +110,21 @@ class Experiment(object):
 
 class DistributedExperiment(Experiment):
     """Describes a distributed simulation experiment."""
-    num_hosts = 1
-    """Number of hosts to use."""
-    host_mapping: tp.Dict[Simulator, int]
-    """Mapping from simulator to host ID."""
-    proxies_listen: tp.List[NetProxyListener]
-    proxies_connect: tp.List[NetProxyConnecter]
 
     def __init__(self, name: str, num_hosts: int):
-        self.num_hosts = num_hosts
-        self.host_mapping = {}
-        self.proxies_listen = []
-        self.proxies_connect = []
         super().__init__(name)
+        self.num_hosts = num_hosts
+        """Number of hosts to use."""
+        self.host_mapping: tp.Dict[Simulator, int] = {}
+        """Mapping from simulator to host ID."""
+        self.proxies_listen: tp.List[NetProxyListener] = []
+        self.proxies_connect: tp.List[NetProxyConnecter] = []
 
-    def add_proxy(self, proxy: SimProxy):
+    def add_proxy(self, proxy: tp.Union[NetProxyListener, NetProxyConnecter]):
         if proxy.listen:
-            self.proxies_listen.append(proxy)
+            self.proxies_listen.append(tp.cast(NetProxyListener, proxy))
         else:
-            self.proxies_connect.append(proxy)
+            self.proxies_connect.append(tp.cast(NetProxyConnecter, proxy))
 
     def all_simulators(self):
         return itertools.chain(
@@ -152,7 +150,7 @@ T = tp.TypeVar('T', bound=Experiment)
 class ExperimentBaseRunner(tp.Generic[T]):
 
     def __init__(self, exp: T, env: ExpEnv, verbose: bool):
-        self.exp = exp
+        self.exp: T = exp
         self.env = env
         self.verbose = verbose
         self.out = ExpOutput(exp)

experiments/simbricks/nodeconfig.py

@@ -24,6 +24,7 @@ from __future__ import annotations
 
 import io
 import tarfile
+import typing as tp
 
 
 class AppConfig(object):
@@ -47,25 +48,27 @@ class AppConfig(object):
 
 
 class NodeConfig(object):
+
+    def __init__(self):
         """Manages the configuration for a node."""
-    sim = 'qemu'
+        self.sim = 'qemu'
         """Name of simulator to run."""
-    ip = '10.0.0.1'
+        self.ip = '10.0.0.1'
         """IP address."""
-    prefix = 24
+        self.prefix = 24
         """IP prefix."""
-    cores = 1
+        self.cores = 1
         """Number of cores to be simulated."""
-    memory = 8 * 1024
+        self.memory = 8 * 1024
         """Amount of system memory in MB."""
-    disk_image = 'base'
+        self.disk_image = 'base'
         """Disk image to use."""
-    app: AppConfig = None
-    """App to be run on simulated host."""
-    mtu = 1500
+        self.mtu = 1500
         """Networking MTU."""
-    nockp = 0
+        self.nockp = 0
         """Do not make checkpoint in Gem5."""
+        self.app: tp.Optional[AppConfig] = None
+        """App to be run on simulated host."""
 
     def config_str(self):
         if self.sim == 'qemu':
@@ -131,9 +134,10 @@ class NodeConfig(object):
 
 
 class LinuxNode(NodeConfig):
-    ifname = 'eth0'
 
     def __init__(self):
+        super().__init__()
+        self.ifname = 'eth0'
         self.drivers = []
         self.force_mac_addr = None
 
@@ -181,10 +185,13 @@ class E1000LinuxNode(LinuxNode):
 
 
 class MtcpNode(NodeConfig):
-    disk_image = 'mtcp'
-    pci_dev = '0000:00:02.0'
-    memory = 16 * 1024
-    num_hugepages = 4096
+
+    def __init__(self):
+        super().__init__()
+        self.disk_image = 'mtcp'
+        self.pci_dev = '0000:00:02.0'
+        self.memory = 16 * 1024
+        self.num_hugepages = 4096
 
     def prepare_pre_cp(self):
         return super().prepare_pre_cp() + [
@@ -231,12 +238,15 @@ class MtcpNode(NodeConfig):
 
 
 class TASNode(NodeConfig):
-    disk_image = 'tas'
-    pci_dev = '0000:00:02.0'
-    memory = 16 * 1024
-    num_hugepages = 4096
-    fp_cores = 1
-    preload = True
+
+    def __init__(self):
+        super().__init__()
+        self.disk_image = 'tas'
+        self.pci_dev = '0000:00:02.0'
+        self.memory = 16 * 1024
+        self.num_hugepages = 4096
+        self.fp_cores = 1
+        self.preload = True
 
     def prepare_pre_cp(self):
         return super().prepare_pre_cp() + [
@@ -325,6 +335,7 @@ class CorundumDCTCPNode(NodeConfig):
 class LinuxFEMUNode(NodeConfig):
 
     def __init__(self):
+        super().__init__()
         self.drivers = ['nvme']
 
     def prepare_post_cp(self):
@@ -355,8 +366,11 @@ class DctcpServer(AppConfig):
 
 
 class DctcpClient(AppConfig):
-    server_ip = '192.168.64.1'
-    is_last = False
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '192.168.64.1'
+        self.is_last = False
 
     def run_cmds(self, node):
         if self.is_last:
@@ -374,7 +388,10 @@ class DctcpClient(AppConfig):
 
 
 class PingClient(AppConfig):
-    server_ip = '192.168.64.1'
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '192.168.64.1'
 
     def run_cmds(self, node):
         return [f'ping {self.server_ip} -c 100']
@@ -393,9 +410,12 @@ class IperfUDPServer(AppConfig):
 
 
 class IperfTCPClient(AppConfig):
-    server_ip = '10.0.0.1'
-    procs = 1
-    is_last = False
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.procs = 1
+        self.is_last = False
 
     def run_cmds(self, node):
 
@@ -412,9 +432,12 @@ class IperfTCPClient(AppConfig):
 
 
 class IperfUDPClient(AppConfig):
-    server_ip = '10.0.0.1'
-    rate = '150m'
-    is_last = False
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.rate = '150m'
+        self.is_last = False
 
     def run_cmds(self, node):
         cmds = [
@@ -431,9 +454,12 @@ class IperfUDPClient(AppConfig):
 
 
 class IperfUDPShortClient(AppConfig):
-    server_ip = '10.0.0.1'
-    rate = '150m'
-    is_last = False
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.rate = '150m'
+        self.is_last = False
 
     def run_cmds(self, node):
         cmds = ['sleep 1', 'iperf -c ' + self.server_ip + ' -u -n 1 ']
@@ -442,16 +468,22 @@ class IperfUDPShortClient(AppConfig):
 
 
 class IperfUDPClientSleep(AppConfig):
-    server_ip = '10.0.0.1'
-    rate = '150m'
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.rate = '150m'
 
     def run_cmds(self, node):
         return ['sleep 1', 'sleep 10']
 
 
 class NoTraffic(AppConfig):
-    is_sleep = 1
-    is_server = 0
+
+    def __init__(self):
+        super().__init__()
+        self.is_sleep = 1
+        self.is_server = 0
 
     def run_cmds(self, node):
         cmds = []
@@ -474,9 +506,12 @@ class NetperfServer(AppConfig):
 
 
 class NetperfClient(AppConfig):
-    server_ip = '10.0.0.1'
-    duration_tp = 10
-    duration_lat = 10
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.duration_tp = 10
+        self.duration_lat = 10
 
     def run_cmds(self, node):
         return [
@@ -491,7 +526,10 @@ class NetperfClient(AppConfig):
 
 
 class VRReplica(AppConfig):
-    index = 0
+
+    def __init__(self):
+        super().__init__()
+        self.index = 0
 
     def run_cmds(self, node):
         return [
@@ -501,7 +539,10 @@ class VRReplica(AppConfig):
 
 
 class VRClient(AppConfig):
-    server_ips = []
+
+    def __init__(self):
+        super().__init__()
+        self.server_ips = []
 
     def run_cmds(self, node):
         cmds = []
@@ -515,7 +556,10 @@ class VRClient(AppConfig):
 
 
 class NOPaxosReplica(AppConfig):
-    index = 0
+
+    def __init__(self):
+        super().__init__()
+        self.index = 0
 
     def run_cmds(self, node):
         return [
@@ -525,9 +569,12 @@ class NOPaxosReplica(AppConfig):
 
 
 class NOPaxosClient(AppConfig):
-    server_ips = []
-    is_last = False
-    use_ehseq = False
+
+    def __init__(self):
+        super().__init__()
+        self.server_ips = []
+        self.is_last = False
+        self.use_ehseq = False
 
     def run_cmds(self, node):
         cmds = []
@@ -555,10 +602,13 @@ class NOPaxosSequencer(AppConfig):
 
 
 class RPCServer(AppConfig):
-    port = 1234
-    threads = 1
-    max_flows = 1234
-    max_bytes = 1024
+
+    def __init__(self):
+        super().__init__()
+        self.port = 1234
+        self.threads = 1
+        self.max_flows = 1234
+        self.max_bytes = 1024
 
     def run_cmds(self, node):
         exe = 'echoserver_linux' if not isinstance(node, MtcpNode) else \
@@ -573,16 +623,19 @@ class RPCServer(AppConfig):
 
 
 class RPCClient(AppConfig):
-    server_ip = '10.0.0.1'
-    port = 1234
-    threads = 1
-    max_flows = 128
-    max_bytes = 1024
-    max_pending = 1
-    openall_delay = 2
-    max_msgs_conn = 0
-    max_pend_conns = 8
-    time = 25
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.port = 1234
+        self.threads = 1
+        self.max_flows = 128
+        self.max_bytes = 1024
+        self.max_pending = 1
+        self.openall_delay = 2
+        self.max_msgs_conn = 0
+        self.max_pend_conns = 8
+        self.time = 25
 
     def run_cmds(self, node):
         exe = 'testclient_linux' if not isinstance(node, MtcpNode) else \
@@ -603,10 +656,13 @@ class RPCClient(AppConfig):
 
 
 class HTTPD(AppConfig):
-    threads = 1
-    file_size = 64
-    mtcp_config = 'lighttpd.conf'
-    httpd_dir: str  # TODO added because doesn't originally exist
+
+    def __init__(self):
+        super().__init__()
+        self.threads = 1
+        self.file_size = 64
+        self.mtcp_config = 'lighttpd.conf'
+        self.httpd_dir = ''  # TODO added because doesn't originally exist
 
     def prepare_pre_cp(self):
         return [
@@ -628,16 +684,25 @@ class HTTPD(AppConfig):
 
 
 class HTTPDLinux(HTTPD):
-    httpd_dir = '/root/mtcp/apps/lighttpd-mtlinux'
+
+    def __init__(self):
+        super().__init__()
+        self.httpd_dir = '/root/mtcp/apps/lighttpd-mtlinux'
 
 
 class HTTPDLinuxRPO(HTTPD):
-    httpd_dir = '/root/mtcp/apps/lighttpd-mtlinux-rop'
+
+    def __init__(self):
+        super().__init__()
+        self.httpd_dir = '/root/mtcp/apps/lighttpd-mtlinux-rop'
 
 
 class HTTPDMtcp(HTTPD):
-    httpd_dir = '/root/mtcp/apps/lighttpd-mtcp'
-    mtcp_config = 'm-lighttpd.conf'
+
+    def __init__(self):
+        super().__init__()
+        self.httpd_dir = '/root/mtcp/apps/lighttpd-mtcp'
+        self.mtcp_config = 'm-lighttpd.conf'
 
     def prepare_pre_cp(self):
         return super().prepare_pre_cp() + [
@@ -651,13 +716,16 @@ class HTTPDMtcp(HTTPD):
 
 
 class HTTPC(AppConfig):
-    server_ip = '10.0.0.1'
-    conns = 1000
-    #requests = 10000000
-    requests = 10000
-    threads = 1
-    url = '/file'
-    ab_dir: str  # TODO added because doesn't originally exist
+
+    def __init__(self):
+        super().__init__()
+        self.server_ip = '10.0.0.1'
+        self.conns = 1000
+        #self.requests = 10000000
+        self.requests = 10000
+        self.threads = 1
+        self.url = '/file'
+        self.ab_dir = ''  # TODO added because doesn't originally exist
 
     def run_cmds(self, node):
         return [
@@ -670,11 +738,17 @@ class HTTPC(AppConfig):
 
 
 class HTTPCLinux(HTTPC):
-    ab_dir = '/root/mtcp/apps/ab-linux'
+
+    def __init__(self):
+        super().__init__()
+        self.ab_dir = '/root/mtcp/apps/ab-linux'
 
 
 class HTTPCMtcp(HTTPC):
-    ab_dir = '/root/mtcp/apps/ab-mtcp'
+
+    def __init__(self):
+        super().__init__()
+        self.ab_dir = '/root/mtcp/apps/ab-mtcp'
 
     def prepare_pre_cp(self):
         return super().prepare_pre_cp() + [
@@ -690,10 +764,13 @@ class MemcachedServer(AppConfig):
 
 
 class MemcachedClient(AppConfig):
-    server_ips = ['10.0.0.1']
-    threads = 1
-    concurrency = 1
-    throughput = '1k'
+
+    def __init__(self):
+        super().__init__()
+        self.server_ips = ['10.0.0.1']
+        self.threads = 1
+        self.concurrency = 1
+        self.throughput = '1k'
 
     def run_cmds(self, node):
         servers = [ip + ':11211' for ip in self.server_ips]

experiments/simbricks/proxy.py

@@ -20,14 +20,19 @@
 # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-from simbricks.simulators import Simulator
+import typing as tp
+
+from simbricks.simulators import NICSim, Simulator
 
 
 class SimProxy(Simulator):
-    name = ''
+
+    def __init__(self):
+        super().__init__()
+        self.name = ''
         # set by the experiment runner
-    ip = ''
-    listen = False
+        self.ip = ''
+        self.listen = False
 
     def full_name(self):
         return 'proxy.' + self.name
@@ -35,29 +40,29 @@ class SimProxy(Simulator):
 
 class NetProxy(SimProxy):
     """Proxy for connections between NICs and networks."""
-    # List of tuples (nic, with_listener)
-    nics = None
 
-    # List of tuples ((netL,netC), with_listener)
-    n2ns = None
-
-    # Shared memory size in GB
-    shm_size = 2048
+    def __init__(self):
+        super().__init__()
+        self.nics: tp.List[tp.Tuple[NICSim, bool]] = []
+        """List of tuples (nic, with_listener)"""
+        self.n2ns: tp.List[tp.Tuple[tp.Tuple[NetProxyListener,
+                                             NetProxyConnecter],
+                                    bool]] = []
+        """List of tuples ((netL,netC), with_listener)"""
+        self.shm_size = 2048
+        """Shared memory size in GB"""
 
     def start_delay(self):
         return 10
 
 
 class NetProxyListener(NetProxy):
-    port = 12345
-    connecter = None
-    listen = True
 
     def __init__(self):
         super().__init__()
+        self.port = 12345
+        self.connecter = None
         self.listen = True
-        self.nics = []
-        self.n2ns = []
 
     def add_nic(self, nic):
         self.nics.append((nic, True))
@@ -119,9 +124,8 @@ class NetProxyListener(NetProxy):
 
 
 class NetProxyConnecter(NetProxy):
-    listener = None
 
-    def __init__(self, listener):
+    def __init__(self, listener: NetProxyListener):
         super().__init__()
         self.listener = listener
         listener.connecter = self

experiments/simbricks/simulators.py

@@ -80,11 +80,16 @@ class Simulator(object):
 
 
 class PCIDevSim(Simulator):
-    name = ''
-    sync_mode = 0
-    start_tick = 0
-    sync_period = 500
-    pci_latency = 500
+    """Base class for PCIe device simulators."""
+
+    def __init__(self):
+        super().__init__()
+
+        self.name = ''
+        self.sync_mode = 0
+        self.start_tick = 0
+        self.sync_period = 500
+        self.pci_latency = 500
 
     def full_name(self):
         return 'dev.' + self.name
@@ -97,9 +102,14 @@ class PCIDevSim(Simulator):
 
 
 class NICSim(PCIDevSim):
-    network = None
-    mac = None
-    eth_latency = 500
+    """Base class for NIC simulators."""
+
+    def __init__(self):
+        super().__init__()
+
+        self.network: tp.Optional[NetSim] = None
+        self.mac: tp.Optional[str] = None
+        self.eth_latency = 500
 
     def set_network(self, net: NetSim):
         self.network = net
@@ -134,15 +144,19 @@ class NICSim(PCIDevSim):
 
 class NetSim(Simulator):
     """Base class for network simulators."""
-    name = ''
-    opt = ''
-    sync_mode = 0
-    sync_period = 500
-    eth_latency = 500
-    nics: list[NICSim] = []
-    hosts_direct: list[HostSim] = []
-    net_listen: list[NetSim] = []
-    net_connect: list[NetSim] = []
+
+    def __init__(self):
+        super().__init__()
+
+        self.name = ''
+        self.opt = ''
+        self.sync_mode = 0
+        self.sync_period = 500
+        self.eth_latency = 500
+        self.nics: list[NICSim] = []
+        self.hosts_direct: list[HostSim] = []
+        self.net_listen: list[NetSim] = []
+        self.net_connect: list[NetSim] = []
 
     def full_name(self):
         return 'net.' + self.name
@@ -179,25 +193,27 @@ class NetSim(Simulator):
 
 
 class HostSim(Simulator):
-    node_config: NodeConfig
+    """Base class for host simulators."""
+
+    def __init__(self):
+        super().__init__()
+        self.node_config: tp.Optional[NodeConfig] = None
         """Config for the simulated host. """
-    name = ''
-    wait = False
+        self.name = ''
+        self.wait = False
         """
         `True` - Wait for process of simulator to exit.
         `False` - Don't wait and instead stop the process.
         """
-    sleep = 0
-    cpu_freq = '8GHz'
+        self.sleep = 0
+        self.cpu_freq = '8GHz'
 
-    sync_mode = 0
-    sync_period = 500
-    pci_latency = 500
+        self.sync_mode = 0
+        self.sync_period = 500
+        self.pci_latency = 500
 
-    def __init__(self):
         self.pcidevs: tp.List[PCIDevSim] = []
         self.net_directs: tp.List[NetSim] = []
-        super().__init__()
 
     def full_name(self):
         return 'host.' + self.name
@@ -229,8 +245,13 @@ class HostSim(Simulator):
 
 
 class QemuHost(HostSim):
-    sync = False
-    cpu_freq = '4GHz'
+    """Qemu host simulator."""
+
+    def __init__(self):
+        super().__init__()
+
+        self.sync = False
+        self.cpu_freq = '4GHz'
 
     def resreq_cores(self):
         if self.sync:
@@ -291,12 +312,13 @@ class QemuHost(HostSim):
 
 
 class Gem5Host(HostSim):
-    cpu_type_cp = 'X86KvmCPU'
-    cpu_type = 'TimingSimpleCPU'
-    sys_clock = '1GHz'
+    """Gem5 host simulator."""
 
     def __init__(self):
         super().__init__()
+        self.cpu_type_cp = 'X86KvmCPU'
+        self.cpu_type = 'TimingSimpleCPU'
+        self.sys_clock = '1GHz'
         self.extra_main_args = []
         self.extra_config_args = []
         self.variant = 'fast'
@@ -369,7 +391,10 @@ class Gem5Host(HostSim):
 
 
 class CorundumVerilatorNIC(NICSim):
-    clock_freq = 250  # MHz
+
+    def __init__(self):
+        super().__init__()
+        self.clock_freq = 250  # MHz
 
     def resreq_mem(self):
         # this is a guess
@@ -394,7 +419,10 @@ class I40eNIC(NICSim):
 
 
 class E1000NIC(NICSim):
-    debug = False
+
+    def __init__(self):
+        super().__init__()
+        self.debug = False
 
     def run_cmd(self, env):
         cmd = self.basic_run_cmd(env, '/e1000_gem5/e1000_gem5')
@@ -404,12 +432,11 @@ class E1000NIC(NICSim):
 
 
 class MultiSubNIC(NICSim):
-    name = ''
-    multinic = None
 
     def __init__(self, mn):
-        self.multinic = mn
         super().__init__()
+        self.name = ''
+        self.multinic = mn
 
     def full_name(self):
         return self.multinic.full_name() + '.' + self.name
@@ -422,11 +449,11 @@ class MultiSubNIC(NICSim):
 
 
 class I40eMultiNIC(Simulator):
-    name = ''
 
     def __init__(self):
-        self.subnics = []
         super().__init__()
+        self.subnics = []
+        self.name = ''
 
     def create_subnic(self):
         sn = MultiSubNIC(self)
@@ -475,7 +502,10 @@ class WireNet(NetSim):
 
 
 class SwitchNet(NetSim):
-    sync = True
+
+    def __init__(self):
+        super().__init__()
+        self.sync = True
 
     def run_cmd(self, env):
         cmd = env.repodir + '/sims/net/switch/net_switch'
@@ -503,8 +533,11 @@ class SwitchNet(NetSim):
 
 
 class TofinoNet(NetSim):
-    tofino_log_path = '/tmp/model.ldjson'
-    sync = True
+
+    def __init__(self):
+        super().__init__()
+        self.tofino_log_path = '/tmp/model.ldjson'
+        self.sync = True
 
     def run_cmd(self, env):
         cmd = f'{env.repodir}/sims/net/tofino/tofino'