diff --git a/imperative/python/src/ops.cpp b/imperative/python/src/ops.cpp
index 3bc859aac746ee74701165931d60fba56ebeb1a7..03d5b0c70706c60603189d4630bb024787493555 100644
--- a/imperative/python/src/ops.cpp
+++ b/imperative/python/src/ops.cpp
@@ -557,7 +557,14 @@ void init_ops(py::module m) {
     m.def(
             "delete_rng_handle",
             [](size_t handle) {
+                if (mgb::imperative::python::interpreter_for_py->check_available()) {
+                    mgb::imperative::python::interpreter_for_py->sync();
+                }
                 mgb::CompNode::sync_all();
+                mgb::CompNode::foreach ([](mgb::CompNode cn) {
+                    auto err = cn.check_async_error();
+                    mgb_assert(!err, "%s", err->what());
+                });
                 py_task_q.wait_all_task_finish();
                 rng::delete_handle(handle);
             },
diff --git a/imperative/python/test/conftest.py b/imperative/python/test/conftest.py
index 4424d5b3c7297ca15dfb3d5707be7ad9eacf7e6b..465ede6bcf9f808a181df5ef5e2d97a4eba89212 100644
--- a/imperative/python/test/conftest.py
+++ b/imperative/python/test/conftest.py
@@ -11,13 +11,17 @@ import sys
 
 import pytest
 
-import megengine.functional
-import megengine.module
-from megengine import Parameter
-from megengine.core._imperative_rt.core2 import sync
+from megengine.core import _config as config
+from megengine.core import _trace_option as trace_option
+from megengine.core import get_option
+from megengine.core._imperative_rt.core2 import (
+    _get_amp_dtype_autocast,
+    _get_amp_high_prec_dtype,
+    _get_amp_low_prec_dtype,
+    _get_convert_inputs,
+)
+from megengine.core.tensor import amp
 from megengine.device import get_device_count
-from megengine.jit import trace as _trace
-from megengine.module import Linear, Module
 
 sys.path.append(os.path.join(os.path.dirname(__file__), "helpers"))
 
@@ -41,3 +45,58 @@ def skip_distributed(request):
                     platform.system()
                 )
             )
+
+
+@pytest.fixture(autouse=True)
+def run_around_tests():
+    env_vars1 = {
+        "symbolic_shape": trace_option.use_symbolic_shape(),
+        "async_level": get_option("async_level"),
+        "enable_drop": get_option("enable_drop"),
+        "max_recompute_time": get_option("max_recompute_time"),
+        "catch_worker_execption": get_option("catch_worker_execption"),
+        "enable_host_compute": get_option("enable_host_compute"),
+        # "record_computing_path": get_option("record_computing_path"),
+        "disable_memory_forwarding": get_option("disable_memory_forwarding"),
+        "enable_dtr_auto_drop": get_option("enable_dtr_auto_drop"),
+        "enable_dtr_sqrt_sampling": get_option("enable_dtr_sqrt_sampling"),
+        "dtr_eviction_threshold": get_option("dtr_eviction_threshold"),
+        "dtr_evictee_minimum_size": get_option("dtr_evictee_minimum_size"),
+        "benchmark_kernel": config.benchmark_kernel,
+        "deterministic_kernel": config.deterministic_kernel,
+        "compute_mode": config._compute_mode,
+        "conv_format": config._conv_format,
+        "amp_enabled": amp.enabled,
+        "convert_inputs": _get_convert_inputs(),
+        "amp_dtype_autocast": _get_amp_dtype_autocast(),
+        "amp_high_prec_dtype": _get_amp_high_prec_dtype(),
+        "amp_low_prec_dtype": _get_amp_low_prec_dtype(),
+    }
+    yield
+    env_vars2 = {
+        "symbolic_shape": trace_option.use_symbolic_shape(),
+        "async_level": get_option("async_level"),
+        "enable_drop": get_option("enable_drop"),
+        "max_recompute_time": get_option("max_recompute_time"),
+        "catch_worker_execption": get_option("catch_worker_execption"),
+        "enable_host_compute": get_option("enable_host_compute"),
+        # "record_computing_path": get_option("record_computing_path"),
+        "disable_memory_forwarding": get_option("disable_memory_forwarding"),
+        "enable_dtr_auto_drop": get_option("enable_dtr_auto_drop"),
+        "enable_dtr_sqrt_sampling": get_option("enable_dtr_sqrt_sampling"),
+        "dtr_eviction_threshold": get_option("dtr_eviction_threshold"),
+        "dtr_evictee_minimum_size": get_option("dtr_evictee_minimum_size"),
+        "benchmark_kernel": config.benchmark_kernel,
+        "deterministic_kernel": config.deterministic_kernel,
+        "compute_mode": config._compute_mode,
+        "conv_format": config._conv_format,
+        "amp_enabled": amp.enabled,
+        "convert_inputs": _get_convert_inputs(),
+        "amp_dtype_autocast": _get_amp_dtype_autocast(),
+        "amp_high_prec_dtype": _get_amp_high_prec_dtype(),
+        "amp_low_prec_dtype": _get_amp_low_prec_dtype(),
+    }
+    for key in env_vars1:
+        assert (
+            env_vars1[key] == env_vars2[key]
+        ), "{} have been changed after test".format(key)
diff --git a/imperative/python/test/run.sh b/imperative/python/test/run.sh
index bd42e951ac5157b09025e9e9d4a43182ca04c943..5b052290659222daa426c9a1430bdff8d3e867d6 100755
--- a/imperative/python/test/run.sh
+++ b/imperative/python/test/run.sh
@@ -37,7 +37,7 @@ if [[ "$TEST_PLAT" =~ "local" ]]; then
     PY_IGNORE_IMPORTMISMATCH=1 python3 -m pytest -s -v $test_dirs -m 'not isolated_distributed'
     if [[ "$TEST_PLAT" =~ "cuda" ]]; then
         echo "test GPU pytest now"
-        PY_IGNORE_IMPORTMISMATCH=1 python3 -m pytest -s -v $test_dirs -m 'isolated_distributed'
+        PY_IGNORE_IMPORTMISMATCH=1 python3 -m pytest -s -v $test_dirs -m 'isolated_distributed' --ignore=./integration/test_dtr.py
     fi
 else
     cd $(dirname "${BASH_SOURCE[0]}")/..
diff --git a/imperative/python/test/unit/random/test_rng.py b/imperative/python/test/unit/random/test_rng.py
index 3dd89b20d49ff0fae7d2eb30618a4296c403e6e9..504631c1c47f7b3341586b018080c621090fe74f 100644
--- a/imperative/python/test/unit/random/test_rng.py
+++ b/imperative/python/test/unit/random/test_rng.py
@@ -39,8 +39,6 @@ from megengine.random import uniform
     get_device_count("xpu") <= 2, reason="xpu counts need > 2",
 )
 def test_gaussian_op():
-    # FIXME: remove this sync
-    mge.core.set_option("async_level", 0)
     set_global_seed(1024)
     shape = (
         8,
@@ -516,4 +514,3 @@ def test_rng_empty_tensor(is_symbolic):
         np.testing.assert_equal(out.numpy().shape, (0,))
         if is_symbolic is None:
             break
-    mge.core.set_option("async_level", 2)
diff --git a/imperative/src/impl/ops/reduce.cpp b/imperative/src/impl/ops/reduce.cpp
index ffd2400e0f72e9ca5573fa7ccc392ac28655a5c8..bc94769299d7afd1899bad7ca548497090253f54 100644
--- a/imperative/src/impl/ops/reduce.cpp
+++ b/imperative/src/impl/ops/reduce.cpp
@@ -175,10 +175,9 @@ SmallVector<TensorPtr> apply_on_physical_tensor(
     megdnn::Workspace dnn_wk;
 
     auto wk_size = dnn_op.op->get_workspace_in_bytes(src, layout);
-    if (wk_size != 0) {
-        auto wk = Blob::make(comp_node, wk_size);
-        dnn_wk.raw_ptr = wk->storage().get();
-        dnn_wk.size = wk_size;
+    if (wk_size) {
+        TensorLayout w_layout({wk_size}, dtype::Byte());
+        dnn_wk = dnn_op.create_workspace(w_layout);
     }
 
     DeviceTensorND out =