vulkan: FA MMQ should use fp32 for Q quantization calculations (#27413 )

Codex found that qd could be a denorm and 1/qd would overflow.
metal : dequant kv cache only for large batches (#27438 )
2026-08-21 23:57:44 +02:00 · 2026-08-20 09:18:11 -05:00 · 2026-08-20 17:00:54 +03:00 · 2026-08-20 15:42:26 +02:00
10 changed files with 148 additions and 21 deletions
@@ -119,6 +119,7 @@ jobs:
          ./bin/llama-completion -m stories260K.gguf -p "One day, Lily met a Shoggoth" -n 500 -c 256

  windows:
+    name: windows / ${{ matrix.build }}
    runs-on: windows-2025

    env:
@@ -130,13 +131,13 @@ jobs:
        include:
          - build: 'x64-cpu-static'
            arch: 'x64'
-            defines: '-G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/x64-windows-llvm.cmake -DGGML_NATIVE=OFF -DLLAMA_BUILD_SERVER=ON -DGGML_RPC=ON -DBUILD_SHARED_LIBS=OFF'
+            defines: '-G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/x64-windows-llvm.cmake -DGGML_NATIVE=OFF -DGGML_OPENMP_FETCH=ON -DLLAMA_BUILD_SERVER=ON -DGGML_RPC=ON -DBUILD_SHARED_LIBS=OFF'
          - build: 'x64-openblas'
            arch: 'x64'
            defines: '-G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/x64-windows-llvm.cmake -DGGML_NATIVE=OFF -DLLAMA_BUILD_SERVER=ON -DGGML_RPC=ON -DGGML_BACKEND_DL=ON -DGGML_CPU_ALL_VARIANTS=ON -DGGML_OPENMP=OFF -DGGML_BLAS=ON -DGGML_BLAS_VENDOR=OpenBLAS -DBLAS_INCLUDE_DIRS="$env:RUNNER_TEMP/openblas/include" -DBLAS_LIBRARIES="$env:RUNNER_TEMP/openblas/lib/openblas.lib"'
          - build: 'arm64'
            arch: 'arm64'
-            defines: '-G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/arm64-windows-llvm.cmake -DGGML_NATIVE=OFF -DLLAMA_BUILD_SERVER=ON'
+            defines: '-G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/arm64-windows-llvm.cmake -DGGML_NATIVE=OFF -DGGML_OPENMP_FETCH=ON -DLLAMA_BUILD_SERVER=ON'

    steps:
      - name: Clone
@@ -681,6 +681,7 @@ jobs:
          name: llama-bin-win-openvino-${{ env.OPENVINO_VERSION_MAJOR }}-x64.zip

  windows-cpu:
+    name: windows-cpu / ${{ matrix.arch }}
    needs: [check-release]
    if: ${{ needs.check-release.outputs.should_release == 'true' }}

@@ -728,6 +729,7 @@ jobs:
            -DGGML_BACKEND_DL=ON ^
            -DGGML_CPU_ALL_VARIANTS=${{ matrix.arch == 'x64' && 'ON' || 'OFF' }} ^
            -DGGML_OPENMP=ON ^
+            -DGGML_OPENMP_FETCH=ON ^
            ${{ env.CMAKE_ARGS }}
          cmake --build build --config Release

@@ -739,7 +741,6 @@ jobs:
      - name: Pack artifacts
        id: pack_artifacts
        run: |
-          Copy-Item "C:\Program Files\Microsoft Visual Studio\18\Enterprise\VC\Redist\MSVC\14.51.36231\debug_nonredist\${{ matrix.arch }}\Microsoft.VC145.OpenMP.LLVM\libomp140.${{ matrix.arch == 'x64' && 'x86_64' || 'aarch64' }}.dll" .\build\bin\Release\
          7z a -snl llama-bin-win-cpu-${{ matrix.arch }}.zip .\build\bin\Release\*

      - name: Upload artifacts
@@ -8,6 +8,7 @@ set( CMAKE_CXX_COMPILER  clang++ )

 set( CMAKE_C_COMPILER_TARGET   ${target} )
 set( CMAKE_CXX_COMPILER_TARGET ${target} )
+set( CMAKE_ASM_COMPILER_TARGET ${target} )

 set( arch_c_flags "-march=armv8.7-a -fvectorize -ffp-model=fast -fno-finite-math-only" )
 set( warn_c_flags "-Wno-format -Wno-unused-variable -Wno-unused-function -Wno-gnu-zero-variadic-macro-arguments" )
@@ -72,9 +72,10 @@ cmake --build build --config Release
    - Please remember to always use a Developer Command Prompt / PowerShell for VS2022 for git, build, test
    - For Windows on ARM (arm64, WoA) build with:
    ```bash
-    cmake --preset arm64-windows-llvm-release -D GGML_OPENMP=OFF
+    cmake --preset arm64-windows-llvm-release -D GGML_OPENMP_FETCH=ON
    cmake --build build-arm64-windows-llvm-release
    ```
+    `GGML_OPENMP_FETCH` downloads the official LLVM OpenMP runtime and requires Clang, 7-Zip and network access during configuration. CMake selects the runtime from the target architecture, so this also works when cross-compiling for WoA from x64. The extracted header, import library, DLL and OpenMP license are placed under `build/_deps`. The build copies `libomp.dll` and `LICENSE-LLVM-OpenMP` to the runtime output directory and installs them together. Omit the option to use CMake's normal OpenMP detection, or pass `-D GGML_OPENMP=OFF` to disable OpenMP.
    For building with ninja generator and clang compiler as default:
      -set path:set LIB=C:\Program Files (x86)\Windows Kits\10\Lib\10.0.22621.0\um\x64;C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.41.34120\lib\x64\uwp;C:\Program Files (x86)\Windows Kits\10\Lib\10.0.22621.0\ucrt\x64
      ```bash
@@ -243,6 +243,7 @@ set   (GGML_METAL_MACOSX_VERSION_MIN "" CACHE STRING
                                            "ggml: metal minimum macOS version")
 set   (GGML_METAL_STD "" CACHE STRING       "ggml: metal standard version (-std flag)")
 option(GGML_OPENMP                          "ggml: use OpenMP"                                ON)
+option(GGML_OPENMP_FETCH                    "ggml: fetch LLVM OpenMP"                         OFF)
 option(GGML_RPC                             "ggml: use RPC"                                   OFF)
 option(GGML_SYCL                            "ggml: use SYCL"                                  OFF)
 option(GGML_SYCL_F16                        "ggml: use 16 bit floats for sycl calculations"   OFF)
@@ -222,9 +222,123 @@ if (GGML_SCHED_NO_REALLOC)
    target_compile_definitions(ggml-base PUBLIC GGML_SCHED_NO_REALLOC)
 endif()

-if (GGML_OPENMP)
+if (GGML_OPENMP_FETCH)
+    if (NOT GGML_OPENMP)
+        message(FATAL_ERROR "GGML_OPENMP_FETCH requires GGML_OPENMP")
+    elseif (NOT WIN32 OR NOT (CMAKE_C_COMPILER_ID MATCHES "Clang"))
+        message(FATAL_ERROR "GGML_OPENMP_FETCH currently requires Clang on Windows")
+    endif()
+
+    set(GGML_OPENMP_LLVM_VERSION "20.1.8")
+    string(REGEX MATCH "^[0-9]+" GGML_OPENMP_LLVM_VERSION_MAJOR "${GGML_OPENMP_LLVM_VERSION}")
+    string(REGEX MATCH "^[0-9]+" GGML_OPENMP_COMPILER_VERSION_MAJOR "${CMAKE_C_COMPILER_VERSION}")
+    if (NOT GGML_OPENMP_COMPILER_VERSION_MAJOR STREQUAL GGML_OPENMP_LLVM_VERSION_MAJOR)
+        message(FATAL_ERROR "LLVM OpenMP ${GGML_OPENMP_LLVM_VERSION} requires Clang ${GGML_OPENMP_LLVM_VERSION_MAJOR}.x")
+    endif()
+
+    string(TOLOWER "${CMAKE_SYSTEM_PROCESSOR}" GGML_OPENMP_SYSTEM_PROCESSOR)
+    if (GGML_OPENMP_SYSTEM_PROCESSOR MATCHES "^(amd64|x86_64)$")
+        set(GGML_OPENMP_ARCH "x64")
+        set(GGML_OPENMP_INSTALLER_SUFFIX "win64")
+        set(GGML_OPENMP_INSTALLER_SHA256 "3197846a2b19063687dd56e93e34cd941e3548d907f23a6131571321bdf9fe7b")
+    elseif (GGML_OPENMP_SYSTEM_PROCESSOR MATCHES "^(aarch64|arm64)$")
+        set(GGML_OPENMP_ARCH "arm64")
+        set(GGML_OPENMP_INSTALLER_SUFFIX "woa64")
+        set(GGML_OPENMP_INSTALLER_SHA256 "7c4ac97eb2ae6b960ca5f9caf3ff6124c8d2a18cc07a7840a4d2ea15537bad8e")
+    else()
+        message(FATAL_ERROR "GGML_OPENMP_FETCH does not support ${CMAKE_SYSTEM_PROCESSOR}")
+    endif()
+
+    set(GGML_OPENMP_CACHE_DIR "${CMAKE_BINARY_DIR}/_deps")
+    set(GGML_OPENMP_ROOT "${GGML_OPENMP_CACHE_DIR}/llvm-openmp-${GGML_OPENMP_LLVM_VERSION}-${GGML_OPENMP_ARCH}")
+    set(GGML_OPENMP_LIBRARY "${GGML_OPENMP_ROOT}/lib/libomp.lib")
+    set(GGML_OPENMP_RUNTIME "${GGML_OPENMP_ROOT}/bin/libomp.dll")
+    set(GGML_OPENMP_HEADER "${GGML_OPENMP_ROOT}/include/omp.h")
+    set(GGML_OPENMP_LICENSE "${GGML_OPENMP_ROOT}/LICENSE.TXT")
+    set(GGML_OPENMP_LICENSE_SHA256 "fdad1758a9e1f9d5a81e18879b3406772115edc92c24bfa36b70c654f325e8e4")
+
+    if (NOT EXISTS "${GGML_OPENMP_LIBRARY}" OR NOT EXISTS "${GGML_OPENMP_RUNTIME}" OR NOT EXISTS "${GGML_OPENMP_HEADER}")
+        find_program(GGML_OPENMP_7Z NAMES 7z 7zz 7za)
+        if (NOT GGML_OPENMP_7Z)
+            message(FATAL_ERROR "GGML_OPENMP_FETCH requires 7-Zip to extract the LLVM installer")
+        endif()
+
+        set(GGML_OPENMP_INSTALLER "${GGML_OPENMP_ROOT}/LLVM-${GGML_OPENMP_LLVM_VERSION}-${GGML_OPENMP_INSTALLER_SUFFIX}.exe")
+        set(GGML_OPENMP_EXTRACT_DIR "${GGML_OPENMP_ROOT}/extract")
+        set(GGML_OPENMP_INSTALLER_URL "https://github.com/llvm/llvm-project/releases/download/llvmorg-${GGML_OPENMP_LLVM_VERSION}/LLVM-${GGML_OPENMP_LLVM_VERSION}-${GGML_OPENMP_INSTALLER_SUFFIX}.exe")
+
+        file(MAKE_DIRECTORY "${GGML_OPENMP_EXTRACT_DIR}")
+        file(DOWNLOAD "${GGML_OPENMP_INSTALLER_URL}" "${GGML_OPENMP_INSTALLER}"
+            EXPECTED_HASH "SHA256=${GGML_OPENMP_INSTALLER_SHA256}"
+            SHOW_PROGRESS
+            STATUS GGML_OPENMP_DOWNLOAD_STATUS)
+        list(GET GGML_OPENMP_DOWNLOAD_STATUS 0 GGML_OPENMP_DOWNLOAD_RESULT)
+        if (NOT GGML_OPENMP_DOWNLOAD_RESULT EQUAL 0)
+            list(GET GGML_OPENMP_DOWNLOAD_STATUS 1 GGML_OPENMP_DOWNLOAD_ERROR)
+            message(FATAL_ERROR "Failed to download LLVM OpenMP: ${GGML_OPENMP_DOWNLOAD_ERROR}")
+        endif()
+
+        execute_process(
+            COMMAND "${GGML_OPENMP_7Z}" e -y "-o${GGML_OPENMP_EXTRACT_DIR}" "${GGML_OPENMP_INSTALLER}" -r libomp.lib libomp.dll omp.h
+            RESULT_VARIABLE GGML_OPENMP_EXTRACT_RESULT
+            OUTPUT_QUIET)
+        if (NOT GGML_OPENMP_EXTRACT_RESULT EQUAL 0 OR
+            NOT EXISTS "${GGML_OPENMP_EXTRACT_DIR}/libomp.lib" OR
+            NOT EXISTS "${GGML_OPENMP_EXTRACT_DIR}/libomp.dll" OR
+            NOT EXISTS "${GGML_OPENMP_EXTRACT_DIR}/omp.h")
+            message(FATAL_ERROR "Failed to extract libomp from ${GGML_OPENMP_INSTALLER}")
+        endif()
+
+        file(MAKE_DIRECTORY "${GGML_OPENMP_ROOT}/lib" "${GGML_OPENMP_ROOT}/bin" "${GGML_OPENMP_ROOT}/include")
+        file(COPY "${GGML_OPENMP_EXTRACT_DIR}/libomp.lib" DESTINATION "${GGML_OPENMP_ROOT}/lib")
+        file(COPY "${GGML_OPENMP_EXTRACT_DIR}/libomp.dll" DESTINATION "${GGML_OPENMP_ROOT}/bin")
+        file(COPY "${GGML_OPENMP_EXTRACT_DIR}/omp.h" DESTINATION "${GGML_OPENMP_ROOT}/include")
+        file(REMOVE_RECURSE "${GGML_OPENMP_INSTALLER}" "${GGML_OPENMP_EXTRACT_DIR}")
+    endif()
+
+    # The NSIS installer embeds LLVM's general license in its UI but does not install it as a file; use OpenMP's license to include its additional notices.
+    if (EXISTS "${GGML_OPENMP_LICENSE}")
+        file(SHA256 "${GGML_OPENMP_LICENSE}" GGML_OPENMP_LICENSE_ACTUAL_SHA256)
+    endif()
+    if (NOT GGML_OPENMP_LICENSE_ACTUAL_SHA256 STREQUAL GGML_OPENMP_LICENSE_SHA256)
+        file(DOWNLOAD "https://raw.githubusercontent.com/llvm/llvm-project/llvmorg-${GGML_OPENMP_LLVM_VERSION}/openmp/LICENSE.TXT" "${GGML_OPENMP_LICENSE}"
+            EXPECTED_HASH "SHA256=${GGML_OPENMP_LICENSE_SHA256}")
+    endif()
+
+    if (COMMAND license_add_file)
+        license_add_file("LLVM OpenMP" "${GGML_OPENMP_LICENSE}")
+    endif()
+
+    add_library(ggml-openmp-c INTERFACE)
+    target_compile_options(ggml-openmp-c INTERFACE "$<$<COMPILE_LANGUAGE:C>:-fopenmp=libomp>")
+    target_include_directories(ggml-openmp-c SYSTEM INTERFACE "${GGML_OPENMP_ROOT}/include")
+    target_link_libraries(ggml-openmp-c INTERFACE "${GGML_OPENMP_LIBRARY}")
+
+    add_library(ggml-openmp-cxx INTERFACE)
+    target_compile_options(ggml-openmp-cxx INTERFACE "$<$<COMPILE_LANGUAGE:CXX>:-fopenmp=libomp>")
+    target_include_directories(ggml-openmp-cxx SYSTEM INTERFACE "${GGML_OPENMP_ROOT}/include")
+    target_link_libraries(ggml-openmp-cxx INTERFACE "${GGML_OPENMP_LIBRARY}")
+
+    set(GGML_OPENMP_RUNTIME_OUTPUT_DIR "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}")
+    if (CMAKE_CONFIGURATION_TYPES)
+        string(APPEND GGML_OPENMP_RUNTIME_OUTPUT_DIR "/$<CONFIG>")
+    endif()
+    add_custom_target(ggml-openmp-runtime ALL
+        COMMAND ${CMAKE_COMMAND} -E make_directory "${GGML_OPENMP_RUNTIME_OUTPUT_DIR}"
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different "${GGML_OPENMP_RUNTIME}" "${GGML_OPENMP_RUNTIME_OUTPUT_DIR}/libomp.dll"
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different "${GGML_OPENMP_LICENSE}" "${GGML_OPENMP_RUNTIME_OUTPUT_DIR}/LICENSE-LLVM-OpenMP")
+    add_dependencies(ggml-base ggml-openmp-runtime)
+    install(FILES "${GGML_OPENMP_RUNTIME}" DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(FILES "${GGML_OPENMP_LICENSE}" DESTINATION ${CMAKE_INSTALL_BINDIR} RENAME LICENSE-LLVM-OpenMP)
+
+    set(GGML_OPENMP_TARGET_C ggml-openmp-c)
+    set(GGML_OPENMP_TARGET_CXX ggml-openmp-cxx)
+    set(GGML_OPENMP_ENABLED "ON" CACHE INTERNAL "")
+elseif (GGML_OPENMP)
    find_package(OpenMP)
    if (OpenMP_FOUND)
+        set(GGML_OPENMP_TARGET_C OpenMP::OpenMP_C)
+        set(GGML_OPENMP_TARGET_CXX OpenMP::OpenMP_CXX)
        set(GGML_OPENMP_ENABLED "ON" CACHE INTERNAL "")
    else()
        set(GGML_OPENMP_ENABLED "OFF" CACHE INTERNAL "")
@@ -236,7 +350,7 @@ endif()

 if (GGML_OPENMP_ENABLED)
    target_compile_definitions(ggml-base PRIVATE GGML_USE_OPENMP)
-    target_link_libraries(ggml-base PRIVATE OpenMP::OpenMP_C OpenMP::OpenMP_CXX)
+    target_link_libraries(ggml-base PRIVATE ${GGML_OPENMP_TARGET_C} ${GGML_OPENMP_TARGET_CXX})
 endif()

 add_library(ggml
@@ -74,7 +74,7 @@ function(ggml_add_cpu_backend_variant_impl tag_name)

    if (GGML_OPENMP_ENABLED)
        target_compile_definitions(${GGML_CPU_NAME} PRIVATE GGML_USE_OPENMP)
-        target_link_libraries(${GGML_CPU_NAME} PRIVATE OpenMP::OpenMP_C OpenMP::OpenMP_CXX)
+        target_link_libraries(${GGML_CPU_NAME} PRIVATE ${GGML_OPENMP_TARGET_C} ${GGML_OPENMP_TARGET_CXX})
    endif()

    if (GGML_LLAMAFILE)
@@ -2806,6 +2806,13 @@ bool ggml_metal_op_flash_attn_ext_use_vec(const ggml_tensor * op) {
 static bool ggml_metal_op_flash_attn_ext_use_kv_f16(const ggml_tensor * op) {
    assert(op->op == GGML_OP_FLASH_ATTN_EXT);

+    // depending on compute/bandwidth ratio, dequant to f16 kv is not always beneficial
+    // ref: https://github.com/ggml-org/llama.cpp/pull/27390#issuecomment-5355152767
+    // TODO: tune per device
+    if (op->src[0]->ne[1] < 32) {
+        return false;
+    }
+
    switch (op->src[1]->type) {
        case GGML_TYPE_Q4_0:
        case GGML_TYPE_Q4_1:
@@ -2968,9 +2975,10 @@ size_t ggml_metal_op_flash_attn_ext_extra_tmp(const ggml_tensor * op) {
 size_t ggml_metal_op_flash_attn_ext_extra_kv_f16(const ggml_tensor * op) {
    assert(op->op == GGML_OP_FLASH_ATTN_EXT);

-    if (!ggml_metal_op_flash_attn_ext_use_kv_f16(op)) {
-        return 0;
-    }
+    // note: always reserve the temp buffer to avoid graph reallocations
+    //if (!ggml_metal_op_flash_attn_ext_use_kv_f16(op)) {
+    //    return 0;
+    //}

    GGML_TENSOR_LOCALS( int32_t, ne2, op->src[2], ne);

@@ -121,13 +121,13 @@ void main() {
        const uint buf_ib = r * qf_stride + d / 8;
        const uint buf_iqs = d % 8;

-        FLOAT_TYPEV4 vals = is_in_bounds ? FLOAT_TYPEV4(data_qv4[q_offset / 4 + (i * Br + r) * q_stride / 4 + d] * p.scale) : FLOAT_TYPEV4(0.0f);
-        const FLOAT_TYPEV4 abs_vals = abs(vals);
+        vec4 vals = is_in_bounds ? data_qv4[q_offset / 4 + (i * Br + r) * q_stride / 4 + d] * p.scale : vec4(0.0f);
+        const vec4 abs_vals = abs(vals);

-        const FLOAT_TYPE thread_max = max(max(abs_vals.x, abs_vals.y), max(abs_vals.z, abs_vals.w));
-        const FLOAT_TYPE amax = subgroupClusteredMax(thread_max, 8);
-        const FLOAT_TYPE qd = amax / FLOAT_TYPE(127.0);
-        const FLOAT_TYPE qd_inv = qd != FLOAT_TYPE(0.0) ? FLOAT_TYPE(1.0) / qd : FLOAT_TYPE(0.0);
+        const float thread_max = max(max(abs_vals.x, abs_vals.y), max(abs_vals.z, abs_vals.w));
+        const float amax = subgroupClusteredMax(thread_max, 8);
+        const float qd = amax / 127.0f;
+        const float qd_inv = qd != 0.0f ? 1.0f / qd : 0.0f;
        vals = round(vals * qd_inv);

        Qf[buf_ib].qs[buf_iqs] = pack32(i8vec4(vals));
@@ -136,11 +136,11 @@ void main() {
        // the row-sum scaled by qd, used in k_dot_correction.
        if (FaTypeK == FA_TYPE_Q8_0) {
            if (buf_iqs == 0) {
-                Qf[buf_ib].ds = FLOAT_TYPEV2(qd, 0.0);
+                Qf[buf_ib].ds = FLOAT_TYPEV2(qd, 0.0f);
            }
        } else {
-            const FLOAT_TYPE thread_sum = vals.x + vals.y + vals.z + vals.w;
-            const FLOAT_TYPE sum = subgroupClusteredAdd(thread_sum, 8);
+            const float thread_sum = vals.x + vals.y + vals.z + vals.w;
+            const float sum = subgroupClusteredAdd(thread_sum, 8);

            if (buf_iqs == 0) {
                Qf[buf_ib].ds = FLOAT_TYPEV2(qd, sum * qd);
@@ -86,6 +86,6 @@ endif()

 target_link_libraries(ggml-zendnn PRIVATE m pthread)

-if (GGML_OPENMP)
-    target_link_libraries(ggml-zendnn PRIVATE OpenMP::OpenMP_CXX)
+if (GGML_OPENMP_ENABLED)
+    target_link_libraries(ggml-zendnn PRIVATE ${GGML_OPENMP_TARGET_CXX})
 endif()