diff --git a/.gitignore b/.gitignore
index e9510a1df..fd72be398 100644
--- a/.gitignore
+++ b/.gitignore
@@ -148,3 +148,4 @@ MUJOCO_LOG.TXT
 *.pkl
 *.hdf5
 wandb/
+videos/
diff --git a/examples/atari/atari_bcq.py b/examples/atari/atari_bcq.py
index 1be441013..ec89243b4 100644
--- a/examples/atari/atari_bcq.py
+++ b/examples/atari/atari_bcq.py
@@ -11,7 +11,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import DiscreteBCQPolicy
 from tianshou.trainer import offline_trainer
 from tianshou.utils import TensorboardLogger
@@ -77,7 +77,7 @@ def test_discrete_bcq(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
diff --git a/examples/atari/atari_c51.py b/examples/atari/atari_c51.py
index 291fb7007..dcd1911dc 100644
--- a/examples/atari/atari_c51.py
+++ b/examples/atari/atari_c51.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import C51Policy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -75,10 +75,10 @@ def test_c51(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -141,7 +141,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/atari/atari_cql.py b/examples/atari/atari_cql.py
index db4e33a9a..685e006db 100644
--- a/examples/atari/atari_cql.py
+++ b/examples/atari/atari_cql.py
@@ -11,7 +11,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import DiscreteCQLPolicy
 from tianshou.trainer import offline_trainer
 from tianshou.utils import TensorboardLogger
@@ -76,7 +76,7 @@ def test_discrete_cql(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
diff --git a/examples/atari/atari_crr.py b/examples/atari/atari_crr.py
index 06cde415b..8905c7e58 100644
--- a/examples/atari/atari_crr.py
+++ b/examples/atari/atari_crr.py
@@ -11,7 +11,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import DiscreteCRRPolicy
 from tianshou.trainer import offline_trainer
 from tianshou.utils import TensorboardLogger
@@ -77,7 +77,7 @@ def test_discrete_crr(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
diff --git a/examples/atari/atari_dqn.py b/examples/atari/atari_dqn.py
index c9f74af8c..67a44d002 100644
--- a/examples/atari/atari_dqn.py
+++ b/examples/atari/atari_dqn.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import DQNPolicy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -72,10 +72,10 @@ def test_dqn(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -135,7 +135,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/atari/atari_fqf.py b/examples/atari/atari_fqf.py
index 4629bede2..99f8957c4 100644
--- a/examples/atari/atari_fqf.py
+++ b/examples/atari/atari_fqf.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import FQFPolicy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -78,10 +78,10 @@ def test_fqf(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -158,7 +158,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/atari/atari_iqn.py b/examples/atari/atari_iqn.py
index d0e7773d0..532d59482 100644
--- a/examples/atari/atari_iqn.py
+++ b/examples/atari/atari_iqn.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import IQNPolicy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -78,10 +78,10 @@ def test_iqn(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -153,7 +153,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/atari/atari_qrdqn.py b/examples/atari/atari_qrdqn.py
index 23a7966eb..af5d78e3f 100644
--- a/examples/atari/atari_qrdqn.py
+++ b/examples/atari/atari_qrdqn.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import QRDQNPolicy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -73,10 +73,10 @@ def test_qrdqn(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -137,7 +137,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/atari/atari_rainbow.py b/examples/atari/atari_rainbow.py
index b131cce5f..4e1a78ced 100644
--- a/examples/atari/atari_rainbow.py
+++ b/examples/atari/atari_rainbow.py
@@ -10,7 +10,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, PrioritizedVectorReplayBuffer, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import RainbowPolicy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -85,10 +85,10 @@ def test_rainbow(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [lambda: make_atari_env(args) for _ in range(args.training_num)]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [lambda: make_atari_env_watch(args) for _ in range(args.test_num)]
     )
     # seed
@@ -174,7 +174,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
         if not args.no_priority:
             if env_step <= args.beta_anneal_step:
                 beta = args.beta - env_step / args.beta_anneal_step * \
@@ -182,7 +183,8 @@ def train_fn(epoch, env_step):
             else:
                 beta = args.beta_final
             buffer.set_beta(beta)
-            logger.write('train/beta', env_step, beta)
+            if env_step % 1000 == 0:
+                logger.write("train/env_step", env_step, {"train/beta": beta})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)
diff --git a/examples/vizdoom/vizdoom_c51.py b/examples/vizdoom/vizdoom_c51.py
index bb3a1f207..53eafae20 100644
--- a/examples/vizdoom/vizdoom_c51.py
+++ b/examples/vizdoom/vizdoom_c51.py
@@ -9,7 +9,7 @@
 from torch.utils.tensorboard import SummaryWriter
 
 from tianshou.data import Collector, VectorReplayBuffer
-from tianshou.env import SubprocVectorEnv
+from tianshou.env import ShmemVectorEnv
 from tianshou.policy import C51Policy
 from tianshou.trainer import offpolicy_trainer
 from tianshou.utils import TensorboardLogger
@@ -72,13 +72,13 @@ def test_c51(args=get_args()):
     print("Observations shape:", args.state_shape)
     print("Actions shape:", args.action_shape)
     # make environments
-    train_envs = SubprocVectorEnv(
+    train_envs = ShmemVectorEnv(
         [
             lambda: Env(args.cfg_path, args.frames_stack, args.res)
             for _ in range(args.training_num)
         ]
     )
-    test_envs = SubprocVectorEnv(
+    test_envs = ShmemVectorEnv(
         [
             lambda: Env(args.cfg_path, args.frames_stack, args.res, args.save_lmp)
             for _ in range(min(os.cpu_count() - 1, args.test_num))
@@ -144,7 +144,8 @@ def train_fn(epoch, env_step):
         else:
             eps = args.eps_train_final
         policy.set_eps(eps)
-        logger.write('train/eps', env_step, eps)
+        if env_step % 1000 == 0:
+            logger.write("train/env_step", env_step, {"train/eps": eps})
 
     def test_fn(epoch, env_step):
         policy.set_eps(args.eps_test)