fix(ci): ccache bugs A/B/C and bump SYCL compute runtime to 26.x

Fix three root causes for ccache never hitting in CI:

A) CCACHE_DIR/CCACHE_MAXSIZE not persisting across steps — write them
   to GITHUB_ENV in setup-ccache's Configure step.

B) evict-old-files during setup destroyed restored cache entries before
   the build could use them — remove eviction from setup-ccache entirely
   (keep it only in save-rolling-ccache where it belongs).

C) Relative CCACHE_DIR=.ccache resolved to build/.ccache during
   compilation (Ninja/Make run compilers from the build dir) while
   actions/cache saved from GITHUB_WORKSPACE/.ccache — add a Normalize
   ccache path step in both actions that resolves to an absolute path.

Also bump SYCL Docker images from compute runtime 25.40 to 26.18 and
IGC from v2.20.5 to v2.34.4 to fix a ~21% SYCL performance regression
(ggml-org#23160). The 25.x versions are kept as comments for
reference (needed for multi-GPU per ggml-org#21747 until kernel 7.1).

Author: Anbeeld

.devops/intel.Dockerfile

@@ -65,11 +65,18 @@ RUN mkdir -p /app/full \
 
 FROM intel/deep-learning-essentials:$ONEAPI_VERSION AS base
 
-ARG IGC_VERSION=v2.20.5
-ARG IGC_VERSION_FULL=2_2.20.5+19972
-ARG COMPUTE_RUNTIME_VERSION=25.40.35563.10
-ARG COMPUTE_RUNTIME_VERSION_FULL=25.40.35563.10-0
-ARG IGDGMM_VERSION=22.8.2
+# 25.x causes ~21% SYCL regression: https://github.com/ggml-org/llama.cpp/issues/23160
+# 25.x is needed for multi-GPU: https://github.com/ggml-org/llama.cpp/issues/21747
+#ARG IGC_VERSION=v2.20.5
+#ARG IGC_VERSION_FULL=2_2.20.5+19972
+#ARG COMPUTE_RUNTIME_VERSION=25.40.35563.10
+#ARG COMPUTE_RUNTIME_VERSION_FULL=25.40.35563.10-0
+#ARG IGDGMM_VERSION=22.8.2
+ARG IGC_VERSION=v2.34.4
+ARG IGC_VERSION_FULL=2_2.34.4+21428
+ARG COMPUTE_RUNTIME_VERSION=26.18.38308.1
+ARG COMPUTE_RUNTIME_VERSION_FULL=26.18.38308.1-0
+ARG IGDGMM_VERSION=22.10.0
 RUN mkdir /tmp/neo/ && cd /tmp/neo/ \
   && wget https://github.com/intel/intel-graphics-compiler/releases/download/$IGC_VERSION/intel-igc-core-${IGC_VERSION_FULL}_amd64.deb \
   && wget https://github.com/intel/intel-graphics-compiler/releases/download/$IGC_VERSION/intel-igc-opencl-${IGC_VERSION_FULL}_amd64.deb \

.devops/runtime-intel-server.Dockerfile

@@ -4,11 +4,18 @@ ARG ONEAPI_VERSION=2025.3.3-0-devel-ubuntu24.04
 
 FROM intel/deep-learning-essentials:${ONEAPI_VERSION} AS server
 
-ARG IGC_VERSION=v2.20.5
-ARG IGC_VERSION_FULL=2_2.20.5+19972
-ARG COMPUTE_RUNTIME_VERSION=25.40.35563.10
-ARG COMPUTE_RUNTIME_VERSION_FULL=25.40.35563.10-0
-ARG IGDGMM_VERSION=22.8.2
+# 25.x causes ~21% SYCL regression: https://github.com/ggml-org/llama.cpp/issues/23160
+# 25.x is needed for multi-GPU: https://github.com/ggml-org/llama.cpp/issues/21747
+#ARG IGC_VERSION=v2.20.5
+#ARG IGC_VERSION_FULL=2_2.20.5+19972
+#ARG COMPUTE_RUNTIME_VERSION=25.40.35563.10
+#ARG COMPUTE_RUNTIME_VERSION_FULL=25.40.35563.10-0
+#ARG IGDGMM_VERSION=22.8.2
+ARG IGC_VERSION=v2.34.4
+ARG IGC_VERSION_FULL=2_2.34.4+21428
+ARG COMPUTE_RUNTIME_VERSION=26.18.38308.1
+ARG COMPUTE_RUNTIME_VERSION_FULL=26.18.38308.1-0
+ARG IGDGMM_VERSION=22.10.0
 
 RUN mkdir /tmp/neo/ && cd /tmp/neo/ \
     && wget https://github.com/intel/intel-graphics-compiler/releases/download/${IGC_VERSION}/intel-igc-core-${IGC_VERSION_FULL}_amd64.deb \

.github/actions/save-rolling-ccache/action.yml

@@ -18,11 +18,24 @@ inputs:
 runs:
   using: composite
   steps:
+    - name: Normalize ccache path
+      id: ccache-path
+      shell: bash
+      env:
+        INPUT_PATH: ${{ inputs.path }}
+      run: |
+        case "${INPUT_PATH}" in
+          /*|[A-Za-z]:/*|[A-Za-z]:\\*) CCACHE_DIR_ABS="${INPUT_PATH}" ;;
+          *) CCACHE_DIR_ABS="${GITHUB_WORKSPACE}/${INPUT_PATH}" ;;
+        esac
+        echo "path=${CCACHE_DIR_ABS}" >> "$GITHUB_OUTPUT"
+        echo "Resolved ccache path: ${CCACHE_DIR_ABS}"
+
     - name: Evict old cache files
       if: inputs.evict-old-files != ''
       shell: bash
       env:
-        CCACHE_DIR: ${{ inputs.path }}
+        CCACHE_DIR: ${{ steps.ccache-path.outputs.path }}
         EVICT_AGE: ${{ inputs.evict-old-files }}
       run: |
         if command -v ccache >/dev/null 2>&1; then
@@ -74,5 +87,5 @@ runs:
     - name: Save refreshed cache
       uses: actions/cache/save@v4
       with:
-        path: ${{ inputs.path }}
-        key: ${{ inputs.key }}
+        path: ${{ steps.ccache-path.outputs.path }}
+        key: ${{ inputs.key }}

.github/actions/setup-ccache/action.yml

@@ -16,10 +16,6 @@ inputs:
     description: ccache sloppiness setting (e.g. time_macros, file_macro).
     required: false
     default: ""
-  evict-old-files:
-    description: Age threshold for evicting stale cache entries (e.g. 1d, 3600s).
-    required: false
-    default: ""
   path:
     description: ccache directory path.
     required: false
@@ -63,21 +59,34 @@ runs:
           choco install ccache -y
         }
 
+    - name: Normalize ccache path
+      id: ccache-path
+      shell: bash
+      env:
+        INPUT_PATH: ${{ inputs.path }}
+      run: |
+        case "${INPUT_PATH}" in
+          /*|[A-Za-z]:/*|[A-Za-z]:\\*) CCACHE_DIR_ABS="${INPUT_PATH}" ;;
+          *) CCACHE_DIR_ABS="${GITHUB_WORKSPACE}/${INPUT_PATH}" ;;
+        esac
+        echo "path=${CCACHE_DIR_ABS}" >> "$GITHUB_OUTPUT"
+        echo "Resolved ccache path: ${CCACHE_DIR_ABS}"
+        mkdir -p "${CCACHE_DIR_ABS}"
+
     - name: Restore ccache
       id: restore-cache
       uses: actions/cache/restore@v4
       with:
-        path: ${{ inputs.path }}
+        path: ${{ steps.ccache-path.outputs.path }}
         key: ${{ inputs.key }}
         restore-keys: ${{ inputs.restore-keys }}
 
     - name: Configure ccache
       shell: bash
       env:
-        CCACHE_DIR: ${{ inputs.path }}
+        CCACHE_DIR: ${{ steps.ccache-path.outputs.path }}
         CCACHE_MAXSIZE: ${{ inputs.max-size }}
         CCACHE_SLOPPINESS: ${{ inputs.sloppiness }}
-        EVICT_AGE: ${{ inputs.evict-old-files }}
       run: |
         ccache --set-config=cache_dir="${CCACHE_DIR}"
         ccache --set-config=max_size="${CCACHE_MAXSIZE}"
@@ -86,10 +95,8 @@ runs:
           ccache --set-config=compiler_check=content
         fi
         ccache --set-config=sloppiness="${CCACHE_SLOPPINESS}"
-        if [ -n "${EVICT_AGE}" ]; then
-          ccache --evict-older-than "${EVICT_AGE}"
-        fi
         ccache -z
+        ccache --show-config | grep -E 'cache_dir|max_size'
         echo "CCACHE_DIR=${CCACHE_DIR}" >> "$GITHUB_ENV"
         echo "CCACHE_MAXSIZE=${CCACHE_MAXSIZE}" >> "$GITHUB_ENV"
 

.github/workflows/release.yml

@@ -214,7 +214,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-macos-arm64-
             release-macos-arm64-
-          evict-old-files: 1d
 
       - name: Build
         run: |
@@ -293,7 +292,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-${{ matrix.os }}-cpu-
             release-${{ matrix.os }}-cpu-
-          evict-old-files: 1d
 
       - name: Dependencies
         run: |
@@ -377,7 +375,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-ubuntu-vulkan-x64-
             release-ubuntu-vulkan-x64-
-          evict-old-files: 1d
 
       - name: Dependencies
         run: |
@@ -464,7 +461,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-ubuntu-rocm-${{ env.ROCM_VERSION }}-x64-
             release-ubuntu-rocm-${{ env.ROCM_VERSION }}-x64-
-          evict-old-files: 1d
 
       - name: Dependencies
         run: |
@@ -580,7 +576,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-ubuntu-sycl-${{ env.ONEAPI_INSTALLER_VERSION }}-x64-
             release-ubuntu-sycl-${{ env.ONEAPI_INSTALLER_VERSION }}-x64-
-          evict-old-files: 1d
 
       - name: Dependencies
         run: |
@@ -695,7 +690,6 @@ jobs:
             release-ubuntu-cuda-${{ matrix.cuda }}-x64-
           max-size: 5G
           sloppiness: time_macros
-          evict-old-files: 1d
 
       - name: Build
         run: |
@@ -771,7 +765,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-windows-cpu-x64-
             release-windows-cpu-x64-
-          evict-old-files: 1d
 
       - name: Install Ninja
         run: choco install ninja -y
@@ -873,7 +866,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-windows-sycl-${{ env.ONEAPI_INSTALLER_VERSION }}-x64-
             release-windows-sycl-${{ env.ONEAPI_INSTALLER_VERSION }}-x64-
-          evict-old-files: 1d
 
       - name: Install Ninja
         run: choco install ninja -y
@@ -999,7 +991,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-windows-vulkan-${{ env.VULKAN_VERSION }}-x64-
             release-windows-vulkan-${{ env.VULKAN_VERSION }}-x64-
-          evict-old-files: 1d
 
       - name: Install Ninja
         run: choco install ninja -y
@@ -1071,7 +1062,6 @@ jobs:
             release-windows-cuda-${{ matrix.cuda }}-
           max-size: 5G
           sloppiness: time_macros
-          evict-old-files: 1d
 
       - name: Install CUDA Toolkit
         uses: ./.github/actions/windows-setup-cuda
@@ -1196,7 +1186,6 @@ jobs:
           restore-keys: |
             release-${{ needs.release-meta.outputs.ccache_ref }}-windows-hip-${{ env.HIPSDK_INSTALLER_VERSION }}-x64-
             release-windows-hip-${{ env.HIPSDK_INSTALLER_VERSION }}-x64-
-          evict-old-files: 1d
 
       - name: Install ROCm
         run: |