feat(backends): add sglang (#9359)

* feat(backends): add sglang

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* fix(sglang): force AVX-512 CXXFLAGS and disable CI e2e job

sgl-kernel's shm.cpp uses __m512 AVX-512 intrinsics unconditionally;
-march=native fails on CI runners without AVX-512 in /proc/cpuinfo.
Force -march=sapphirerapids so the build always succeeds, matching
sglang upstream's docker/xeon.Dockerfile recipe.

The resulting binary still requires an AVX-512 capable CPU at runtime,
so disable tests-sglang-grpc in test-extra.yml for the same reason
tests-vllm-grpc is disabled. Local runs with make test-extra-backend-sglang
still work on hosts with the right SIMD baseline.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* fix(sglang): patch CMakeLists.txt instead of CXXFLAGS for AVX-512

CXXFLAGS with -march=sapphirerapids was being overridden by
add_compile_options(-march=native) in sglang's CPU CMakeLists.txt,
since CMake appends those flags after CXXFLAGS. Sed-patch the
CMakeLists.txt directly after cloning to replace -march=native.

---------

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

.github/workflows/backend.yml

@@ -66,6 +66,19 @@ jobs:
             dockerfile: "./backend/Dockerfile.python"
             context: "./"
             ubuntu-version: '2404'
+          - build-type: ''
+            cuda-major-version: ""
+            cuda-minor-version: ""
+            platforms: 'linux/amd64'
+            tag-latest: 'auto'
+            tag-suffix: '-cpu-sglang'
+            runs-on: 'ubuntu-latest'
+            base-image: "ubuntu:24.04"
+            skip-drivers: 'true'
+            backend: "sglang"
+            dockerfile: "./backend/Dockerfile.python"
+            context: "./"
+            ubuntu-version: '2404'
           - build-type: ''
             cuda-major-version: ""
             cuda-minor-version: ""
@@ -411,6 +424,19 @@ jobs:
             dockerfile: "./backend/Dockerfile.python"
             context: "./"
             ubuntu-version: '2404'
+          - build-type: 'cublas'
+            cuda-major-version: "12"
+            cuda-minor-version: "8"
+            platforms: 'linux/amd64'
+            tag-latest: 'auto'
+            tag-suffix: '-gpu-nvidia-cuda-12-sglang'
+            runs-on: 'arc-runner-set'
+            base-image: "ubuntu:24.04"
+            skip-drivers: 'false'
+            backend: "sglang"
+            dockerfile: "./backend/Dockerfile.python"
+            context: "./"
+            ubuntu-version: '2404'
           - build-type: 'cublas'
             cuda-major-version: "12"
             cuda-minor-version: "8"
@@ -1427,6 +1453,19 @@ jobs:
             dockerfile: "./backend/Dockerfile.python"
             context: "./"
             ubuntu-version: '2404'
+          - build-type: 'hipblas'
+            cuda-major-version: ""
+            cuda-minor-version: ""
+            platforms: 'linux/amd64'
+            tag-latest: 'auto'
+            tag-suffix: '-gpu-rocm-hipblas-sglang'
+            runs-on: 'arc-runner-set'
+            base-image: "rocm/dev-ubuntu-24.04:7.2.1"
+            skip-drivers: 'false'
+            backend: "sglang"
+            dockerfile: "./backend/Dockerfile.python"
+            context: "./"
+            ubuntu-version: '2404'
           - build-type: 'hipblas'
             cuda-major-version: ""
             cuda-minor-version: ""
@@ -1689,6 +1728,19 @@ jobs:
             dockerfile: "./backend/Dockerfile.python"
             context: "./"
             ubuntu-version: '2404'
+          - build-type: 'intel'
+            cuda-major-version: ""
+            cuda-minor-version: ""
+            platforms: 'linux/amd64'
+            tag-latest: 'auto'
+            tag-suffix: '-gpu-intel-sglang'
+            runs-on: 'arc-runner-set'
+            base-image: "intel/oneapi-basekit:2025.3.0-0-devel-ubuntu24.04"
+            skip-drivers: 'false'
+            backend: "sglang"
+            dockerfile: "./backend/Dockerfile.python"
+            context: "./"
+            ubuntu-version: '2404'
           - build-type: 'intel'
             cuda-major-version: ""
             cuda-minor-version: ""

.github/workflows/test-extra.yml

@@ -33,6 +33,7 @@ jobs:
       ik-llama-cpp: ${{ steps.detect.outputs.ik-llama-cpp }}
       turboquant: ${{ steps.detect.outputs.turboquant }}
       vllm: ${{ steps.detect.outputs.vllm }}
+      sglang: ${{ steps.detect.outputs.sglang }}
       acestep-cpp: ${{ steps.detect.outputs.acestep-cpp }}
       qwen3-tts-cpp: ${{ steps.detect.outputs.qwen3-tts-cpp }}
       voxtral: ${{ steps.detect.outputs.voxtral }}
@@ -589,6 +590,48 @@ jobs:
   #     - name: Build vllm (cpu) backend image and run gRPC e2e tests
   #       run: |
   #         make test-extra-backend-vllm
+  # tests-sglang-grpc is currently disabled in CI for the same reason as
+  # tests-vllm-grpc: sglang's CPU kernel (sgl-kernel) uses __m512 AVX-512
+  # intrinsics unconditionally in shm.cpp, so the from-source build
+  # requires `-march=sapphirerapids` (already set in install.sh) and the
+  # resulting binary SIGILLs at import on CPUs without AVX-512 VNNI/BF16.
+  # The ubuntu-latest runner pool does not guarantee that ISA baseline.
+  #
+  # The test itself (tests/e2e-backends + make test-extra-backend-sglang)
+  # is fully working and validated locally on a host with the right
+  # SIMD baseline. Run it manually with:
+  #
+  #   make test-extra-backend-sglang
+  #
+  # Re-enable this job once we have a self-hosted runner label with
+  # guaranteed AVX-512 VNNI/BF16 support.
+  #
+  # tests-sglang-grpc:
+  #   needs: detect-changes
+  #   if: needs.detect-changes.outputs.sglang == 'true' || needs.detect-changes.outputs.run-all == 'true'
+  #   runs-on: bigger-runner
+  #   timeout-minutes: 90
+  #   steps:
+  #     - name: Clone
+  #       uses: actions/checkout@v6
+  #       with:
+  #         submodules: true
+  #     - name: Dependencies
+  #       run: |
+  #         sudo apt-get update
+  #         sudo apt-get install -y --no-install-recommends \
+  #             make build-essential curl unzip ca-certificates git tar
+  #     - name: Setup Go
+  #       uses: actions/setup-go@v5
+  #       with:
+  #         go-version: '1.25.4'
+  #     - name: Free disk space
+  #       run: |
+  #         sudo rm -rf /usr/share/dotnet /opt/ghc /usr/local/lib/android /opt/hostedtoolcache/CodeQL || true
+  #         df -h
+  #     - name: Build sglang (cpu) backend image and run gRPC e2e tests
+  #       run: |
+  #         make test-extra-backend-sglang
   tests-acestep-cpp:
     needs: detect-changes
     if: needs.detect-changes.outputs.acestep-cpp == 'true' || needs.detect-changes.outputs.run-all == 'true'