diff --git a/.circleci/test.yml b/.circleci/test.yml
index d2cdb905e4..f97d180f5f 100644
--- a/.circleci/test.yml
+++ b/.circleci/test.yml
@@ -36,8 +36,6 @@ jobs:
         type: string
       torchvision:
         type: string
-      mmcv:
-        type: string
     docker:
       - image: cimg/python:<< parameters.python >>
     resource_class: large
@@ -51,31 +49,32 @@ jobs:
       - run:
           name: Configure Python & pip
           command: |
-            python -m pip install --upgrade pip
-            python -m pip install wheel
+            pip install --upgrade pip
+            pip install wheel
       - run:
           name: Install PyTorch
           command: |
             python -V
-            python -m pip install torch==<< parameters.torch >>+cpu torchvision==<< parameters.torchvision >>+cpu -f https://download.pytorch.org/whl/torch_stable.html
+            pip install torch==<< parameters.torch >>+cpu torchvision==<< parameters.torchvision >>+cpu -f https://download.pytorch.org/whl/torch_stable.html
       - run:
           name: Install mmseg dependencies
           command: |
-            python -m pip install git+ssh://git@github.com/open-mmlab/mmengine.git@main
-            python -m pip install << parameters.mmcv >>
-            python -m pip install git+ssh://git@github.com/open-mmlab/mmclassification@dev-1.x
-            python -m pip install -r requirements.txt
+            pip install git+https://github.com/open-mmlab/mmengine.git@main
+            pip install -U openmim
+            mim install 'mmcv >= 2.0.0rc1'
+            pip install git+https://github.com/open-mmlab/mmclassification@dev-1.x
+            pip install -r requirements/tests.txt -r requirements/optional.txt
       - run:
           name: Build and install
           command: |
-            python -m pip install -e .
+            pip install -e .
       - run:
           name: Run unittests
           command: |
-            python -m pip install timm
-            python -m coverage run --branch --source mmseg -m pytest tests/
-            python -m coverage xml
-            python -m coverage report -m
+            pip install timm
+            coverage run --branch --source mmseg -m pytest tests/
+            coverage xml
+            coverage report -m
       - run:
           name: Skip timm unittests and generate coverage report
           command: |
@@ -92,8 +91,6 @@ jobs:
       cudnn:
         type: integer
         default: 7
-      mmcv:
-        type: string
     machine:
       image: ubuntu-2004-cuda-11.4:202110-01
       # docker_layer_caching: true
@@ -104,8 +101,8 @@ jobs:
           # Cloning repos in VM since Docker doesn't have access to the private key
           name: Clone Repos
           command: |
-            git clone -b main --depth 1 ssh://git@github.com/open-mmlab/mmengine.git /home/circleci/mmengine
-            git clone -b dev-1.x --depth 1 ssh://git@github.com/open-mmlab/mmclassification.git /home/circleci/mmclassification
+            git clone -b main --depth 1 https://github.com/open-mmlab/mmengine.git /home/circleci/mmengine
+            git clone -b dev-1.x --depth 1 https://github.com/open-mmlab/mmclassification.git /home/circleci/mmclassification
       - run:
           name: Build Docker image
           command: |
@@ -115,9 +112,10 @@ jobs:
           name: Install mmseg dependencies
           command: |
             docker exec mmseg pip install -e /mmengine
-            docker exec mmseg pip install << parameters.mmcv >>
+            docker exec mmseg pip install -U openmim
+            docker exec mmseg mim install 'mmcv >= 2.0.0rc1'
             docker exec mmseg pip install -e /mmclassification
-            docker exec mmseg python -m pip install -r requirements.txt
+            docker exec mmseg pip install -r requirements/tests.txt -r requirements/optional.txt
       - run:
           name: Build and install
           command: |
@@ -125,8 +123,8 @@ jobs:
       - run:
           name: Run unittests
           command: |
-            docker exec mmseg python -m pip install timm
-            docker exec mmseg python -m pytest tests/
+            docker exec mmseg pip install timm
+            docker exec mmseg pytest tests/
 workflows:
   pr_stage_lint:
     when: << pipeline.parameters.lint_only >>
@@ -137,7 +135,7 @@ workflows:
             branches:
               ignore:
                 - dev-1.x
-                - test-1.x
+                - 1.x
   pr_stage_test:
     when:
       not:
@@ -149,21 +147,19 @@ workflows:
             branches:
               ignore:
                 - dev-1.x
-                - test-1.x
+                - 1.x
       - build_cpu:
           name: minimum_version_cpu
           torch: 1.6.0
           torchvision: 0.7.0
           python: 3.6.9  # The lowest python 3.6.x version available on CircleCI images
-          mmcv: https://download.openmmlab.com/mmcv/dev-2.x/cpu/torch1.6.0/mmcv_full-2.0.0rc0-cp36-cp36m-manylinux1_x86_64.whl
           requires:
             - lint
       - build_cpu:
           name: maximum_version_cpu
-          torch: 1.9.0
-          torchvision: 0.10.0
+          torch: 1.12.1
+          torchvision: 0.13.1
           python: 3.9.0
-          mmcv: https://download.openmmlab.com/mmcv/dev-2.x/cpu/torch1.9.0/mmcv_full-2.0.0rc0-cp39-cp39-manylinux1_x86_64.whl
           requires:
             - minimum_version_cpu
       - hold:
@@ -176,7 +172,6 @@ workflows:
           # Use double quotation mark to explicitly specify its type
           # as string instead of number
           cuda: "10.2"
-          mmcv: https://download.openmmlab.com/mmcv/dev-2.x/cu102/torch1.8.0/mmcv_full-2.0.0rc0-cp37-cp37m-manylinux1_x86_64.whl
           requires:
             - hold
   merge_stage_test:
@@ -189,10 +184,8 @@ workflows:
           torch: 1.6.0
           # Use double quotation mark to explicitly specify its type
           # as string instead of number
-          mmcv: https://download.openmmlab.com/mmcv/dev-2.x/cu101/torch1.6.0/mmcv_full-2.0.0rc0-cp37-cp37m-manylinux1_x86_64.whl
           cuda: "10.1"
           filters:
             branches:
               only:
                 - dev-1.x
-                - test-1.x
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
deleted file mode 100644
index 640dc4d0ad..0000000000
--- a/.github/workflows/build.yml
+++ /dev/null
@@ -1,260 +0,0 @@
-name: build
-
-on:
-  push:
-    paths-ignore:
-      - 'demo/**'
-      - '.dev/**'
-      - 'docker/**'
-      - 'tools/**'
-      - '**.md'
-
-  pull_request:
-    paths-ignore:
-      - 'demo/**'
-      - '.dev/**'
-      - 'docker/**'
-      - 'tools/**'
-      - 'docs/**'
-      - '**.md'
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  build_cpu:
-    runs-on: ubuntu-18.04
-    strategy:
-      matrix:
-        python-version: [3.7]
-        torch: [1.5.1, 1.6.0, 1.7.0, 1.8.0, 1.9.0]
-        include:
-          - torch: 1.5.1
-            torch_version: torch1.5
-            torchvision: 0.6.1
-          - torch: 1.6.0
-            torch_version: torch1.6
-            torchvision: 0.7.0
-          - torch: 1.7.0
-            torch_version: torch1.7
-            torchvision: 0.8.1
-          - torch: 1.8.0
-            torch_version: torch1.8
-            torchvision: 0.9.0
-          - torch: 1.9.0
-            torch_version: torch1.9
-            torchvision: 0.10.0
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
-        with:
-          python-version: ${{ matrix.python-version }}
-      - name: Upgrade pip
-        run: pip install pip --upgrade
-      - name: Install Pillow
-        run: pip install Pillow==6.2.2
-        if: ${{matrix.torchvision == '0.4.2'}}
-      - name: Install PyTorch
-        run: pip install torch==${{matrix.torch}}+cpu torchvision==${{matrix.torchvision}}+cpu -f https://download.pytorch.org/whl/torch_stable.html
-      - name: Install MMCV
-        run: |
-          pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cpu/${{matrix.torch_version}}/index.html
-          python -c 'import mmcv; print(mmcv.__version__)'
-      - name: Install unittest dependencies
-        run: |
-          pip install -r requirements.txt
-      - name: Build and install
-        run: rm -rf .eggs && pip install -e .
-      - name: Run unittests and generate coverage report
-        run: |
-          pip install timm
-          coverage run --branch --source mmseg -m pytest tests/
-          coverage xml
-          coverage report -m
-        if: ${{matrix.torch >= '1.5.0'}}
-      - name: Skip timm unittests and generate coverage report
-        run: |
-          coverage run --branch --source mmseg -m pytest tests/ --ignore tests/test_models/test_backbones/test_timm_backbone.py
-          coverage xml
-          coverage report -m
-        if: ${{matrix.torch < '1.5.0'}}
-
-  build_cuda101:
-    runs-on: ubuntu-18.04
-    container:
-      image: pytorch/pytorch:1.6.0-cuda10.1-cudnn7-devel
-
-    strategy:
-      matrix:
-        python-version: [3.7]
-        torch:
-          [
-            1.5.1+cu101,
-            1.6.0+cu101,
-            1.7.0+cu101,
-            1.8.0+cu101
-          ]
-        include:
-          - torch: 1.5.1+cu101
-            torch_version: torch1.5
-            torchvision: 0.6.1+cu101
-          - torch: 1.6.0+cu101
-            torch_version: torch1.6
-            torchvision: 0.7.0+cu101
-          - torch: 1.7.0+cu101
-            torch_version: torch1.7
-            torchvision: 0.8.1+cu101
-          - torch: 1.8.0+cu101
-            torch_version: torch1.8
-            torchvision: 0.9.0+cu101
-
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
-        with:
-          python-version: ${{ matrix.python-version }}
-      - name: Fetch GPG keys
-        run: |
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/machine-learning/repos/ubuntu1804/x86_64/7fa2af80.pub
-      - name: Install system dependencies
-        run: |
-          apt-get update && apt-get install -y libgl1-mesa-glx ffmpeg libsm6 libxext6 git ninja-build libglib2.0-0 libsm6 libxrender-dev libxext6 python${{matrix.python-version}}-dev
-          apt-get clean
-          rm -rf /var/lib/apt/lists/*
-      - name: Install Pillow
-        run: python -m pip install Pillow==6.2.2
-        if: ${{matrix.torchvision < 0.5}}
-      - name: Install PyTorch
-        run: python -m pip install torch==${{matrix.torch}} torchvision==${{matrix.torchvision}} -f https://download.pytorch.org/whl/torch_stable.html
-      - name: Install mmseg dependencies
-        run: |
-          python -V
-          python -m pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cu101/${{matrix.torch_version}}/index.html
-          python -m pip install -r requirements.txt
-          python -c 'import mmcv; print(mmcv.__version__)'
-      - name: Build and install
-        run: |
-          rm -rf .eggs
-          python setup.py check -m -s
-          TORCH_CUDA_ARCH_LIST=7.0 pip install .
-      - name: Run unittests and generate coverage report
-        run: |
-          python -m pip install timm
-          coverage run --branch --source mmseg -m pytest tests/
-          coverage xml
-          coverage report -m
-        if: ${{matrix.torch >= '1.5.0'}}
-      - name: Skip timm unittests and generate coverage report
-        run: |
-          coverage run --branch --source mmseg -m pytest tests/ --ignore tests/test_models/test_backbones/test_timm_backbone.py
-          coverage xml
-          coverage report -m
-        if: ${{matrix.torch < '1.5.0'}}
-      - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v1.0.10
-        with:
-          file: ./coverage.xml
-          flags: unittests
-          env_vars: OS,PYTHON
-          name: codecov-umbrella
-          fail_ci_if_error: false
-
-  build_cuda102:
-    runs-on: ubuntu-18.04
-    container:
-      image: pytorch/pytorch:1.9.0-cuda10.2-cudnn7-devel
-
-    strategy:
-      matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
-        torch: [1.9.0+cu102]
-        include:
-          - torch: 1.9.0+cu102
-            torch_version: torch1.9
-            torchvision: 0.10.0+cu102
-
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
-        with:
-          python-version: ${{ matrix.python-version }}
-      - name: Fetch GPG keys
-        run: |
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/machine-learning/repos/ubuntu1804/x86_64/7fa2af80.pub
-      - name: Install system dependencies
-        run: |
-          apt-get update && apt-get install -y libgl1-mesa-glx ffmpeg libsm6 libxext6 git ninja-build libglib2.0-0 libsm6 libxrender-dev libxext6
-          apt-get clean
-          rm -rf /var/lib/apt/lists/*
-      - name: Install Pillow
-        run: python -m pip install Pillow==6.2.2
-        if: ${{matrix.torchvision < 0.5}}
-      - name: Install PyTorch
-        run: python -m pip install torch==${{matrix.torch}} torchvision==${{matrix.torchvision}} -f https://download.pytorch.org/whl/torch_stable.html
-      - name: Install mmseg dependencies
-        run: |
-          python -V
-          python -m pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cu102/${{matrix.torch_version}}/index.html
-          python -m pip install -r requirements.txt
-          python -c 'import mmcv; print(mmcv.__version__)'
-      - name: Build and install
-        run: |
-          rm -rf .eggs
-          python setup.py check -m -s
-          TORCH_CUDA_ARCH_LIST=7.0 pip install .
-      - name: Run unittests and generate coverage report
-        run: |
-          python -m pip install timm
-          coverage run --branch --source mmseg -m pytest tests/
-          coverage xml
-          coverage report -m
-      - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v2
-        with:
-          files: ./coverage.xml
-          flags: unittests
-          env_vars: OS,PYTHON
-          name: codecov-umbrella
-          fail_ci_if_error: false
-
-  test_windows:
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [windows-2022]
-        python: [3.8]
-        platform: [cpu, cu111]
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Python ${{ matrix.python }}
-        uses: actions/setup-python@v2
-        with:
-          python-version: ${{ matrix.python }}
-      - name: Upgrade pip
-        run: pip install pip --upgrade --user
-      - name: Install OpenCV
-        run: pip install opencv-python>=3
-      - name: Install PyTorch
-        # As a complement to Linux CI, we test on PyTorch LTS version
-        run: pip install torch==1.8.2+${{ matrix.platform }} torchvision==0.9.2+${{ matrix.platform }} -f https://download.pytorch.org/whl/lts/1.8/torch_lts.html
-      - name: Install MMCV
-        run: |
-          pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cpu/torch1.8/index.html --only-binary mmcv-full
-      - name: Install unittest dependencies
-        run: pip install -r requirements/tests.txt -r requirements/optional.txt
-      - name: Build and install
-        run: pip install -e .
-      - name: Run unittests
-        run: |
-          python -m pip install timm
-          coverage run --branch --source mmseg -m pytest tests/
-      - name: Generate coverage report
-        run: |
-          coverage xml
-          coverage report -m
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 7f7a309280..de1cab2558 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -17,7 +17,7 @@ jobs:
           python-version: 3.7
       - name: Install pre-commit hook
         run: |
-          pip install pre-commit
+          python -m pip install pre-commit
           pre-commit install
       - name: Linting
         run: |
@@ -27,5 +27,5 @@ jobs:
           pre-commit run --all-files
       - name: Check docstring coverage
         run: |
-          pip install interrogate
-          interrogate -v --ignore-init-method --ignore-module --ignore-nested-functions --exclude mmseg/ops --ignore-regex "__repr__" --fail-under 80 mmseg
+          python -m pip install interrogate
+          interrogate -v --ignore-init-method --ignore-module --ignore-nested-functions --exclude mmseg/ops --ignore-regex "__repr__" --fail-under 75 mmseg
diff --git a/.github/workflows/merge_stage_test.yml b/.github/workflows/merge_stage_test.yml
new file mode 100644
index 0000000000..9d66cde3e9
--- /dev/null
+++ b/.github/workflows/merge_stage_test.yml
@@ -0,0 +1,196 @@
+name: merge_stage_test
+
+on:
+  push:
+    paths-ignore:
+      - 'README.md'
+      - 'README_zh-CN.md'
+      - 'docs/**'
+      - 'demo/**'
+      - '.dev_scripts/**'
+      - '.circleci/**'
+    branches:
+      - dev-1.x
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_cpu_py:
+    runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        python-version: [3.6, 3.8, 3.9]
+        torch: [1.8.1]
+        include:
+          - torch: 1.8.1
+            torchvision: 0.9.1
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Install Pillow
+        run: pip install Pillow==6.2.2
+        if: ${{matrix.torchvision == '0.4.2'}}
+      - name: Install PyTorch
+        run: pip install torch==${{matrix.torch}}+cpu torchvision==${{matrix.torchvision}}+cpu -f https://download.pytorch.org/whl/torch_stable.html
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: rm -rf .eggs && pip install -e .
+      - name: Run unittests and generate coverage report
+        run: |
+          pip install timm
+          coverage run --branch --source mmseg -m pytest tests/
+          coverage xml
+          coverage report -m
+  build_cpu_pt:
+    runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        python-version: [3.7]
+        torch: [1.6.0, 1.7.1, 1.8.1, 1.9.1, 1.10.1, 1.11.0]
+        include:
+          - torch: 1.6.0
+            torchvision: 0.7.0
+          - torch: 1.7.1
+            torchvision: 0.8.2
+          - torch: 1.8.1
+            torchvision: 0.9.1
+          - torch: 1.9.1
+            torchvision: 0.10.1
+          - torch: 1.10.1
+            torchvision: 0.11.2
+          - torch: 1.11.0
+            torchvision: 0.12.0
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Install Pillow
+        run: pip install Pillow==6.2.2
+      - name: Install PyTorch
+        run: pip install torch==${{matrix.torch}}+cpu torchvision==${{matrix.torchvision}}+cpu -f https://download.pytorch.org/whl/torch_stable.html
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: rm -rf .eggs && pip install -e .
+      - name: Run unittests and generate coverage report
+        run: |
+          pip install timm
+          coverage run --branch --source mmseg -m pytest tests/
+          coverage xml
+          coverage report -m
+      # Only upload coverage report for python3.7 && pytorch1.8.1 cpu
+      - name: Upload coverage to Codecov
+        if: ${{matrix.torch == '1.8.1' && matrix.python-version == '3.7'}}
+        uses: codecov/codecov-action@v2
+        with:
+          files: ./coverage.xml
+          flags: unittests
+          env_vars: OS,PYTHON
+          name: codecov-umbrella
+          fail_ci_if_error: false
+
+  build_cu102:
+    runs-on: ubuntu-18.04
+    container:
+      image: pytorch/pytorch:1.8.1-cuda10.2-cudnn7-devel
+    strategy:
+      matrix:
+        python-version: [3.7]
+        include:
+          - torch: 1.8.1
+            cuda: 10.2
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Fetch GPG keys
+        run: |
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/machine-learning/repos/ubuntu1804/x86_64/7fa2af80.pub
+      - name: Install Python-dev
+        run: apt-get update && apt-get install -y python${{matrix.python-version}}-dev
+        if: ${{matrix.python-version != 3.9}}
+      - name: Install system dependencies
+        run: |
+          apt-get update && apt-get install -y ffmpeg libsm6 libxext6 git ninja-build libglib2.0-0 libsm6 libxrender-dev libxext6
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: |
+          python setup.py check -m -s
+          TORCH_CUDA_ARCH_LIST=7.0 pip install -e .
+  build_windows:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [windows-2022]
+        python: [3.7]
+        platform: [cpu, cu111]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Install OpenCV
+        run: pip install opencv-python>=3
+      - name: Install PyTorch
+        run: pip install torch==1.8.1+${{matrix.platform}} torchvision==0.9.1+${{matrix.platform}} -f https://download.pytorch.org/whl/lts/1.8/torch_lts.html
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: pip install -e .
+      - name: Run unittests
+        run: |
+          pip install timm
+          coverage run --branch --source mmseg -m pytest tests/ --ignore tests\test_models\test_forward.py tests\test_models\test_backbones\test_beit.py
+      - name: Generate coverage report
+        run: |
+          coverage xml
+          coverage report -m
diff --git a/.github/workflows/pr_stage_test.yml b/.github/workflows/pr_stage_test.yml
new file mode 100644
index 0000000000..ba8b675d63
--- /dev/null
+++ b/.github/workflows/pr_stage_test.yml
@@ -0,0 +1,141 @@
+name: pr_stage_test
+
+on:
+  pull_request:
+    paths-ignore:
+      - 'README.md'
+      - 'README_zh-CN.md'
+      - 'docs/**'
+      - 'demo/**'
+      - '.dev_scripts/**'
+      - '.circleci/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_cpu:
+    runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        python-version: [3.7]
+        include:
+          - torch: 1.8.1
+            torchvision: 0.9.1
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Install Pillow
+        run: pip install Pillow==6.2.2
+        if: ${{matrix.torchvision == '0.4.2'}}
+      - name: Install PyTorch
+        run: pip install torch==${{matrix.torch}}+cpu torchvision==${{matrix.torchvision}}+cpu -f https://download.pytorch.org/whl/torch_stable.html
+      - name: Install other dependencies
+        run: |
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: rm -rf .eggs && pip install -e .
+      - name: Run unittests and generate coverage report
+        run: |
+          pip install timm
+          coverage run --branch --source mmseg -m pytest tests/
+          coverage xml
+          coverage report -m
+      # Upload coverage report for python3.7 && pytorch1.8.1 cpu
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v1.0.14
+        with:
+          file: ./coverage.xml
+          flags: unittests
+          env_vars: OS,PYTHON
+          name: codecov-umbrella
+          fail_ci_if_error: false
+
+  build_cu102:
+    runs-on: ubuntu-18.04
+    container:
+      image: pytorch/pytorch:1.8.1-cuda10.2-cudnn7-devel
+    strategy:
+      matrix:
+        python-version: [3.7]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Fetch GPG keys
+        run: |
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/3bf863cc.pub
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/machine-learning/repos/ubuntu1804/x86_64/7fa2af80.pub
+      - name: Install Python-dev
+        run: apt-get update && apt-get install -y python${{matrix.python-version}}-dev
+        if: ${{matrix.python-version != 3.9}}
+      - name: Install system dependencies
+        run: |
+          apt-get update
+          apt-get install -y ffmpeg libsm6 libxext6 git ninja-build libglib2.0-0 libxrender-dev
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: |
+          python setup.py check -m -s
+          TORCH_CUDA_ARCH_LIST=7.0 pip install -e .
+  build_windows:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [windows-2022]
+        python: [3.7]
+        platform: [cpu, cu111]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Upgrade pip
+        run: pip install pip --upgrade
+      - name: Install OpenCV
+        run: pip install opencv-python>=3
+      - name: Install PyTorch
+        run: pip install torch==1.8.1+${{matrix.platform}} torchvision==0.9.1+${{matrix.platform}} -f https://download.pytorch.org/whl/lts/1.8/torch_lts.html
+      - name: Install mmseg dependencies
+        run: |
+          python -V
+          pip install -U openmim
+          pip install git+https://github.com/open-mmlab/mmengine.git
+          mim install 'mmcv>=2.0.0rc1'
+          pip install git+https://github.com/open-mmlab/mmclassification.git@dev-1.x
+      - name: Install unittest dependencies
+        run: pip install -r requirements/tests.txt -r requirements/optional.txt
+      - name: Build and install
+        run: pip install -e .
+      - name: Run unittests
+        run: |
+          pip install timm
+          coverage run --branch --source mmseg -m pytest tests/ --ignore tests\test_models\test_forward.py tests\test_models\test_backbones\test_beit.py
+      - name: Generate coverage report
+        run: |
+          coverage xml
+          coverage report -m
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 884f5cd1e9..0e3e179633 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -48,7 +48,7 @@ repos:
         name: update-model-index
         description: Collect model information and update model-index.yml
         entry: .dev/md2yml.py
-        additional_dependencies: [mmcv, lxml, opencv-python]
+        additional_dependencies: [lxml, opencv-python, mmengine]
         language: python
         files: ^configs/.*\.md$
         require_serial: true