Remove unnecessary check and adust server count etc. in CI (#8374)

- This PR removes "wasm" check from the test job, since there is no test
job for "wasm" yet.
- Also, move the check for slang-rhi and slangpy test to the job level
to skip the setup etc. if no run is needed.
- Update the macos compiler version in building.md to match the clang
compiler used in CI.
- Reduce the server count in Linux and Mac when running slang-test to
ease the machine load
- Run slangpy test with `-n auto --maxprocesses=4` to speed up

---------

Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>
Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

4 files changed, 74 insertions, 42 deletions

diff --git a/.github/actions/common-test-setup/action.yml b/.github/actions/common-test-setup/action.yml
index ab1a665c7..3fc6dd617 100644
--- a/.github/actions/common-test-setup/action.yml
+++ b/.github/actions/common-test-setup/action.yml
@@ -40,13 +40,8 @@ runs:
         chmod +x github_artifact/${cmake_config}/bin/* 2>/dev/null || echo "No executables to make executable"
 
         # Set up bin_dir based on platform and config
-        if [[ "${{ inputs.platform }}" == "wasm" ]]; then
-          bin_dir=build.em/Release/bin
-          echo "bin_dir=$bin_dir" >> $GITHUB_ENV
-        else
-          bin_dir=$(pwd)/github_artifact/${cmake_config}/bin
-          echo "bin_dir=$bin_dir" >> $GITHUB_ENV
-        fi
+        bin_dir=$(pwd)/github_artifact/${cmake_config}/bin
+        echo "bin_dir=$bin_dir" >> $GITHUB_ENV
 
         # Also set lib_dir for slangpy tests
         lib_dir=$(pwd)/github_artifact/${cmake_config}/lib
@@ -61,21 +56,57 @@ runs:
           # On Windows, DLLs should be in the same directory as executables or in PATH
           # Use $GITHUB_PATH instead of $PATH for preservation across steps and
           # avoid unix-like/windows-like path issues
-          echo "$bin_dir" >> $GITHUB_PATH
-          echo "$lib_dir" >> $GITHUB_PATH
+          # echo "$bin_dir" >> $GITHUB_PATH
+          # echo "$lib_dir" >> $GITHUB_PATH
+          echo "skipping setting PATH in Windows"
         fi
 
+        # List directory contents
+        echo "Contents of bin_dir ($bin_dir):"
+        ls -a "$bin_dir" 2>/dev/null || echo "bin_dir not found"
+        echo "Contents of lib_dir ($lib_dir):"
+        ls -a "$lib_dir" 2>/dev/null || echo "lib_dir not found"
+
     - name: Check runtime environment
-      if: inputs.platform != 'wasm'
       shell: bash
       run: |
-        echo "$bin_dir/slang-test"
-        "$bin_dir/slang-test" tests/render/check-backend-support-on-ci.slang
-        smokeResult=$("$bin_dir/slang-test" tests/render/check-backend-support-on-ci.slang)
+        echo "Checking supported backends"
+        # Capture the output of slang-test while also displaying it
+        if ! smokeResult=$("$bin_dir/slang-test" tests/render/check-backend-support-on-ci.slang 2>&1); then
+          echo "❌ ERROR: slang-test failed to run"
+          echo "Output: $smokeResult"
+          exit 1
+        fi
         supportedBackends="$(echo "$smokeResult" | grep 'Supported backends: ')"
+        echo "$smokeResult"
         echo "$supportedBackends"
-        # Windows-specific version checks - fail if tools are not available
-        if [[ "${{ inputs.os }}" == "windows" ]]; then
+
+        # Check if the output contains "llvm" (case-insensitive)
+        if echo "$supportedBackends" | grep -qi "llvm"; then
+          echo "✅ LLVM backend support detected"
+        else
+          echo "❌ ERROR: LLVM backend support not detected - this is required to run the filecheck!"
+        fi
+
+        # Function to check API support
+        check_api_support() {
+          local api_list=("$@")
+          for api in "${api_list[@]}"; do
+            if echo "$smokeResult" | grep -qi "${api}: Supported"; then
+              echo "✅ ${api} API support detected"
+            else
+              echo "❌ ${api} API support not detected"
+              exit 1
+            fi
+          done
+        }
+
+        # Platform-specific API checks - fail if APIs are not available
+        if [[ "${{ inputs.os }}" == "macos" ]]; then
+          check_api_support "mtl,metal"
+        elif [[ "${{ inputs.os }}" == "windows" ]]; then
+          check_api_support "vk,vulkan" "dx12,d3d12" "dx11,d3d11" "cuda"
+
           echo "Printing CUDA compiler version: ..."
           nvcc --version || (echo "ERROR: CUDA compiler (nvcc) not available on Windows" && exit 1)
           echo "Printing GPU driver version: ..."
diff --git a/.github/workflows/ci-slang-test.yml b/.github/workflows/ci-slang-test.yml
index 9c6dabf34..4e4a880d9 100644
--- a/.github/workflows/ci-slang-test.yml
+++ b/.github/workflows/ci-slang-test.yml
@@ -44,9 +44,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: "recursive"
-          fetch-depth: "2"
 
       - name: Common Test Setup
         uses: ./.github/actions/common-test-setup
@@ -57,7 +54,6 @@ jobs:
           config: ${{ inputs.config }}
 
       - name: Test Slang
-        if: inputs.platform != 'wasm'
         run: |
           export SLANG_RUN_SPIRV_VALIDATION=1
           export SLANG_USE_SPV_SOURCE_LANGUAGE_UNKNOWN=1
@@ -84,7 +80,7 @@ jobs:
           "$bin_dir/slang-test" "${slang_test_args[@]}"
       - name: Run Slang examples
         # Run GLSL backend tests on release for pull requests, and not on merge_group, to reduce CI load.
-        if: inputs.platform != 'wasm' && inputs.full-gpu-tests && inputs.config == 'release' && github.event_name == 'pull_request'
+        if: inputs.full-gpu-tests && inputs.config == 'release' && github.event_name == 'pull_request'
         run: |
           .github/workflows/ci-examples.sh \
            --bin-dir "$bin_dir" \
@@ -93,12 +89,11 @@ jobs:
            --config "${{ inputs.config }}" \
            --skip-file tests/expected-example-failure-github.txt
       - name: Run slangc tests
-        if: inputs.platform != 'wasm'
         run: |
           PATH=$bin_dir:$PATH tools/slangc-test/test.sh
       - name: Test Slang via glsl
         # Run GLSL backend tests on release for pull requests, and not on merge_group, to reduce CI load.
-        if: inputs.platform != 'wasm' && inputs.os != 'macos' && inputs.full-gpu-tests && inputs.config == 'release' && github.event_name == 'pull_request'
+        if: inputs.os != 'macos' && inputs.full-gpu-tests && inputs.config == 'release' && github.event_name == 'pull_request'
         run: |
           export SLANG_RUN_SPIRV_VALIDATION=1
           export SLANG_USE_SPV_SOURCE_LANGUAGE_UNKNOWN=1
@@ -112,8 +107,14 @@ jobs:
             -skip-reference-image-generation \
             -show-adapter-info
 
+  # Run slang-rhi tests when:
+  # 1. full-gpu-tests is enabled AND
+  # 2. Either it's a pull request OR config is release
+  # This is to reduce the CI load but do some check on pull requests.
+  # expensive slang-rhi tests are excluded with -tce option, because they are not relevant for Slang.
   test-slang-rhi:
     runs-on: ${{ fromJSON(inputs.runs-on) }}
+    if: inputs.full-gpu-tests && (github.event_name == 'pull_request' || inputs.config == 'release')
     defaults:
       run:
         shell: bash
@@ -122,7 +123,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: "recursive"
-          fetch-depth: "2"
+          fetch-depth: "1"
 
       - name: Common Test Setup
         uses: ./.github/actions/common-test-setup
@@ -133,9 +134,6 @@ jobs:
           config: ${{ inputs.config }}
 
       - name: Run slang-rhi tests
-        # Run slang-rhi tests on debug+release for pull requests, and only on release for merge_group, to reduce CI load.
-        # Some of the expensive tests that are not relevant for Slang (because they just test graphics API related things) are excluded using -tce.
-        if: inputs.platform != 'wasm' && inputs.full-gpu-tests && (github.event_name == 'pull_request' || inputs.config == 'release')
         run: |
           export SLANG_RHI_EXCLUDE_TESTS="md-clear*,cmd-copy*,cmd-upload*,fence*,staging-heap*,texture-create*"
           if [[ "${{ inputs.os }}" == "macos" ]]; then
@@ -143,8 +141,13 @@ jobs:
           fi
           "$bin_dir/slang-rhi-tests" -check-devices -tce="$SLANG_RHI_EXCLUDE_TESTS"
 
+  # Run slangpy tests when:
+  # 1. full-gpu-tests is enabled AND
+  # 2. Either it's a pull request OR config is release
+  # This is to reduce the CI load but do some check on pull requests.
   test-slangpy:
     runs-on: ${{ fromJSON(inputs.runs-on) }}
+    if: inputs.full-gpu-tests && (github.event_name == 'pull_request' || inputs.config == 'release')
     defaults:
       run:
         shell: bash
@@ -153,7 +156,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: "recursive"
-          fetch-depth: "2"
+          fetch-depth: "1"
 
       - name: Common Test Setup
         uses: ./.github/actions/common-test-setup
@@ -164,8 +167,6 @@ jobs:
           config: ${{ inputs.config }}
 
       - name: Run slangpy tests
-        # Run slangpy tests on debug+release for pull requests, and only on release for merge_group, to reduce CI load.
-        if: inputs.platform != 'wasm' && inputs.full-gpu-tests && (github.event_name == 'pull_request' || inputs.config == 'release')
         run: |
           python --version
           echo "Cleaning up existing installations and installing slangpy..."
@@ -191,21 +192,19 @@ jobs:
           echo "Listing files in slangpy directory..."
           ls -la "$SITE_PACKAGES/slangpy/"
 
-          echo "Installing python packages..."
-
-          # Only install additional packages on GitHub-hosted runners, not self-hosted
-          if [[ "${{ inputs.runs-on }}" != *"self-hosted"* ]]; then
-            # Download and install requirements from slangpy repository
-            echo "Fetching requirements-dev.txt from slangpy repository..."
+          # Skip package installation on self-hosted runners to avoid permission issues
+          if [[ ! "${{ inputs.runs-on }}" =~ self-hosted ]]; then
+            echo "Installing python packages..."
             curl -fsSL https://raw.githubusercontent.com/shader-slang/slangpy/main/requirements-dev.txt -o requirements-dev.txt
-            
-            echo "Installing development requirements..."
-            python -m pip install -r requirements-dev.txt
-            python -m pip install pytest-github-actions-annotate-failures
+            python -m pip install -r requirements-dev.txt --user
+            python -m pip install pytest-github-actions-annotate-failures --user
+            python -m pip install pytest-xdist --user
           else
-            echo "Skipping additional package installation on self-hosted runner"
+            echo "Skipping Python package installation on self-hosted runner"
+            # TODO: remove this once we have pytest-xdist installed on all self-hosted runners
+            python -m pip install pytest-xdist --user
           fi
 
           echo "Running pytest on slangpy tests..."
           export PYTHONPATH="$SITE_PACKAGES"
-          python -m pytest "$SITE_PACKAGES/slangpy/tests" -ra
+          python -m pytest "$SITE_PACKAGES/slangpy/tests" -ra -n auto --maxprocesses=4
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 61ed00769..cbf5fe77e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -135,6 +135,7 @@ jobs:
       config: debug
       runs-on: '["ubuntu-22.04"]'
       test-category: smoke
+      server-count: 2
 
   test-linux-release-gcc-x86_64:
     needs: [filter, build-linux-release-gcc-x86_64]
@@ -147,6 +148,7 @@ jobs:
       config: release
       runs-on: '["ubuntu-22.04"]'
       test-category: full
+      server-count: 4
 
   # macOS tests
   test-macos-debug-clang-aarch64:
diff --git a/docs/building.md b/docs/building.md
index b6e18ad25..bcf366d51 100644
--- a/docs/building.md
+++ b/docs/building.md
@@ -353,7 +353,7 @@ encouraged but it isn't a continuously maintained setup.
 
 _MSVC_ 19 is tested in CI and is the recommended minimum version.
 
-_Clang_ 15.0 is tested in CI and is the recommended minimum version.
+_Clang_ 17.0 is tested in CI and is the recommended minimum version.
 
 ## Static linking against libslang