kleidiai : fix work size and threads sync for fp16 (ggml-org#16246)

Author: chaxu01

ggml/src/ggml-cpu/CMakeLists.txt

@@ -513,9 +513,9 @@ function(ggml_add_cpu_backend_variant_impl tag_name)
 
         # Fetch KleidiAI sources:
         include(FetchContent)
-        set(KLEIDIAI_COMMIT_TAG "v1.13.0")
+        set(KLEIDIAI_COMMIT_TAG "v1.14.0")
         set(KLEIDIAI_DOWNLOAD_URL "https://github.com/ARM-software/kleidiai/archive/refs/tags/${KLEIDIAI_COMMIT_TAG}.tar.gz")
-        set(KLEIDIAI_ARCHIVE_MD5  "d82a8de939d9814621a5ba23907bdac1")
+        set(KLEIDIAI_ARCHIVE_MD5  "45e110675d93f99f82c23a1afcca76bc")
 
         if (POLICY CMP0135)
             cmake_policy(SET CMP0135 NEW)
@@ -592,6 +592,7 @@ function(ggml_add_cpu_backend_variant_impl tag_name)
                 ${KLEIDIAI_SRC}/kai/ukernels/matmul/matmul_clamp_f32_qsi8d32p_qsi4c32p/kai_matmul_clamp_f32_qsi8d32p1vlx4_qsi4c32p4vlx4_1vlx4vl_sme2_mopa.c
                 ${KLEIDIAI_SRC}/kai/ukernels/matmul/matmul_clamp_f32_qsi8d32p_qsi4c32p/kai_matmul_clamp_f32_qsi8d32p1x4_qsi4c32p4vlx4_1x4vl_sme2_sdot.c
                 ${KLEIDIAI_SRC}/kai/ukernels/matmul/matmul_clamp_fp32_bf16p_bf16p/kai_matmul_clamp_f32_bf16p2vlx2_bf16p2vlx2_2vlx2vl_sme2_mopa.c
+                ${KLEIDIAI_SRC}/kai/ukernels/matmul/matmul_clamp_fp32_bf16p_bf16p/kai_matmul_clamp_f32_bf16p2vlx2_bf16p2vlx2_2vlx2vl_sme2_mopa_asm.S
                 ${KLEIDIAI_SRC}/kai/ukernels/matmul/pack/kai_lhs_pack_bf16p2vlx2_f32_sme.c
                 ${KLEIDIAI_SRC}/kai/ukernels/matmul/pack/kai_rhs_pack_kxn_bf16p2vlx2b_f32_x32_sme.c
                 ${KLEIDIAI_SRC}/kai/kai_common_sme_asm.S)

ggml/src/ggml-cpu/kleidiai/kleidiai.cpp

@@ -87,15 +87,38 @@ static inline int64_t ggml_ne(const ggml_tensor * tensor, int dim) {
     return tensor->ne[dim];
 }
 
+template <typename Variant, typename Ret, typename... Args, std::size_t... Is>
+constexpr bool variant_any_invocable_impl(std::index_sequence<Is...>) {
+    using V = std::remove_reference_t<Variant>;
+    return (std::is_invocable_r_v<
+                Ret,
+                std::variant_alternative_t<Is, V>,
+                Args...> || ...);
+}
+
+template <typename Variant, typename Ret, typename... Args>
+constexpr bool variant_any_invocable_v =
+    variant_any_invocable_impl<Variant, Ret, Args...>(
+        std::make_index_sequence<
+            std::variant_size_v<std::remove_reference_t<Variant>>>{});
+
 template<typename Ret, typename Variant, typename... Args>
-static Ret variant_call(const Variant & var, Args&&... args) {
-    return std::visit([&](auto&& func) -> Ret {
-        if constexpr (std::is_invocable_r_v<Ret, decltype(func), Args...>) {
-            return func(std::forward<Args>(args)...);
-        } else {
-            throw std::runtime_error("Invalid function type in variant_call");
-        }
-    }, var);
+static inline Ret variant_call(Variant && var, Args&&... args) {
+    static_assert(variant_any_invocable_v<std::remove_reference_t<Variant>, Ret, Args...>,
+                  "No alternative in Variant is invocable with the provided arguments and return type.");
+
+    return std::visit(
+        [&](auto && f) -> Ret {
+            using F = std::decay_t<decltype(f)>;
+            if constexpr (std::is_invocable_r_v<Ret, F, Args...>) {
+                return std::invoke(std::forward<decltype(f)>(f), std::forward<Args>(args)...);
+            } else {
+                GGML_ABORT("Invalid function type in variant_call");
+                GGML_UNREACHABLE();
+            }
+        },
+        std::forward<Variant>(var)
+    );
 }
 
 namespace ggml::cpu::kleidiai {
@@ -138,7 +161,10 @@ class tensor_traits : public ggml::cpu::tensor_traits {
         if (kernels->rhs_type == GGML_TYPE_Q4_0) {
             size = variant_call<size_t>(lhs_info->packed_size, m, k, QK4_0, mr, kr, sr);
         } else if (kernels->rhs_type == GGML_TYPE_F16) {
-            size = variant_call<size_t>(lhs_info->packed_size, m, k, mr, kr, sr) +
+            const int64_t lhs_batch_size0 = op->src[1]->ne[2];
+            const int64_t rhs_batch_size0 = op->src[0]->ne[2];
+            const int64_t r = lhs_batch_size0 / rhs_batch_size0;
+            size = variant_call<size_t>(lhs_info->packed_size, m * r, k, mr, kr, sr) +
                    variant_call<size_t>(kernels->rhs_info.packed_size, n, k) +
                    k * n * sizeof(float) + n * sizeof(float);
         } else {
@@ -148,7 +174,6 @@ class tensor_traits : public ggml::cpu::tensor_traits {
         return true;
     }
 
-
     bool compute_forward(struct ggml_compute_params * params, struct ggml_tensor * dst) override {
         if (dst->op == GGML_OP_MUL_MAT) {
             if (dst->src[0]->type == GGML_TYPE_Q4_0) {
@@ -165,8 +190,6 @@ class tensor_traits : public ggml::cpu::tensor_traits {
     }
 
     bool compute_forward_fp16(ggml_compute_params * params, struct ggml_tensor * dst) {
-        static std::atomic_flag first_to_arrive = ATOMIC_FLAG_INIT;
-
         const ggml_tensor * src0 = dst->src[0];
         const ggml_tensor * src1 = dst->src[1];
 
@@ -175,7 +198,7 @@ class tensor_traits : public ggml::cpu::tensor_traits {
         ggml_kleidiai_kernels *kernels = ggml_kleidiai_select_kernels(ctx.features, dst);
         GGML_ASSERT(kernels);
 
-        bool is_gemv = src1->ne[1] == 1;
+        const bool is_gemv = src1->ne[1] == 1;
         kernel_info * kernel = is_gemv ? &kernels->gemv : &kernels->gemm;
         lhs_packing_info * lhs_info = is_gemv ? &kernels->gemv_lhs_info : &kernels->gemm_lhs_info;
         GGML_ASSERT(kernel);
@@ -185,27 +208,30 @@ class tensor_traits : public ggml::cpu::tensor_traits {
 
         const int64_t lhs_batch_size0 = ne12;
         const int64_t rhs_batch_size0 = ne02;
-        const int64_t batch_size      = rhs_batch_size0;
+        const int64_t batch_size      = lhs_batch_size0;
 
+        GGML_ASSERT(rhs_batch_size0 > 0);
+        GGML_ASSERT(lhs_batch_size0 % rhs_batch_size0 == 0);
         const int64_t r = lhs_batch_size0 / rhs_batch_size0;
 
-        const int64_t m = ne11 * r;
-        const int64_t n = ne01;
-        const int64_t k = ne00;
+        const int64_t m_group = ne11;
+        const int64_t m       = m_group;
+        const int64_t n       = ne01;
+        const int64_t k       = ne00;
 
         const size_t lhs_stride = src1->nb[1];
         const size_t rhs_stride = src0->nb[1];
         const size_t dst_stride = dst->nb[1];
 
-        const int64_t mr = static_cast<int64_t>(kernel->get_mr());
-        const int64_t nr = static_cast<int64_t>(kernel->get_nr());
-        const int64_t kr = static_cast<int64_t>(kernel->get_kr());
-        const int64_t sr = static_cast<int64_t>(kernel->get_sr());
+        const int64_t mr = (int64_t) kernel->get_mr();
+        const int64_t nr = (int64_t) kernel->get_nr();
+        const int64_t kr = (int64_t) kernel->get_kr();
+        const int64_t sr = (int64_t) kernel->get_sr();
 
-        const size_t lhs_packed_size = variant_call<size_t>(lhs_info->packed_size, m, k, mr, kr, sr);
-        const size_t rhs_packed_size = variant_call<size_t>(kernels->rhs_info.packed_size, n, k);
-        const size_t kxn_size        = k * n * sizeof(float);
-        const size_t bias_size       = n * sizeof(float);
+        const size_t lhs_packed_size = variant_call<size_t>(lhs_info->packed_size, (size_t)m, (size_t)k, (size_t)mr, (size_t)kr, (size_t)sr);
+        const size_t rhs_packed_size = variant_call<size_t>(kernels->rhs_info.packed_size, (size_t)n, (size_t)k);
+        const size_t kxn_size        = (size_t)k * (size_t)n * sizeof(float);
+        const size_t bias_size       = (size_t)n * sizeof(float);
 
         const size_t wsize_required = lhs_packed_size + rhs_packed_size + kxn_size + bias_size;
         GGML_ASSERT(wsize_required <= params->wsize);
@@ -216,82 +242,102 @@ class tensor_traits : public ggml::cpu::tensor_traits {
         uint8_t * bias       = rhs_kxn + kxn_size;
 
         for (int64_t batch_idx = 0; batch_idx < batch_size; ++batch_idx) {
-            const uint8_t * lhs_batch = static_cast<const uint8_t *>(src1->data) + batch_idx * m * lhs_stride;
-            const uint8_t * rhs_batch = static_cast<const uint8_t *>(src0->data) + batch_idx * n * rhs_stride;
-            uint8_t * dst_batch       = static_cast<uint8_t *>(dst->data) + batch_idx * m * dst_stride;
+            const int64_t rhs_batch_idx = batch_idx / r;
+            const uint8_t * rhs_batch_base = static_cast<const uint8_t *>(src0->data) + rhs_batch_idx * src0->nb[2];
+            uint8_t * dst_batch_base = static_cast<uint8_t *>(dst->data) + batch_idx * dst->nb[2];
 
-            // LHS packing
+            // LHS packing (threaded over m, honoring mr alignment and KV groups)
             {
                 const int64_t m_roundup_mr = kai_roundup(m, mr);
                 const int64_t num_threads  = KAI_MIN(m_roundup_mr / mr, nth);
 
                 if (ith < num_threads) {
-                    const int64_t num_m_per_thread0   = round_down(m_roundup_mr / num_threads, mr);
+                    const int64_t num_m_per_thread0   = round_down((size_t)(m_roundup_mr / num_threads), (size_t)mr);
                     const int64_t num_m_per_threadN_1 = m - (num_threads - 1) * num_m_per_thread0;
 
-                    const int64_t m_start          = ith * num_m_per_thread0;
-                    const int64_t num_m_per_thread = (ith == num_threads - 1) ? num_m_per_threadN_1 : num_m_per_thread0;
+                    const int64_t m_start = ith * num_m_per_thread0;
+                    const int64_t m_count = (ith == num_threads - 1) ? num_m_per_threadN_1 : num_m_per_thread0;
+
+                    // Base packed offset (aligned) and per-row stride in bytes
+                    const size_t base_packed_off = variant_call<size_t>(
+                        lhs_info->get_packed_offset, (size_t)m_start, (size_t)k, (size_t)mr, (size_t)kr, (size_t)sr);
+                    const size_t next_block_off = variant_call<size_t>(
+                        lhs_info->get_packed_offset, (size_t)(m_start + mr), (size_t)k, (size_t)mr, (size_t)kr, (size_t)sr);
+                    const size_t row_stride_bytes = (next_block_off - base_packed_off) / (size_t)mr;
+
+                    int64_t remaining = m_count;
+                    int64_t cur       = m_start;
+
+                    while (remaining > 0) {
+                        const int64_t row_in_group = cur;
+                        const int64_t avail        = m_group - row_in_group;
+                        const int64_t take         = std::min(avail, remaining);
 
-                    const size_t lhs_offset        = variant_call<size_t>(kernels->gemm.get_lhs_offset, m_start, lhs_stride);
-                    const size_t lhs_packed_offset = variant_call<size_t>(lhs_info->get_packed_offset, m_start, k, mr, kr, sr);
+                        const uint8_t * lhs_batch_base = static_cast<const uint8_t *>(src1->data) + batch_idx * src1->nb[2];
+                        const void * src_ptr = lhs_batch_base + (size_t)row_in_group * lhs_stride;
+                        const size_t dst_off = base_packed_off + (size_t)(cur - m_start) * row_stride_bytes;
+                        void * dst_ptr       = lhs_packed + dst_off;
 
-                    const void * src_ptr = static_cast<const uint8_t *>(lhs_batch) + lhs_offset;
-                    void * dst_ptr       = static_cast<uint8_t *>(lhs_packed) + lhs_packed_offset;
+                        variant_call<void>(lhs_info->pack_func,
+                                        (size_t)take, (size_t)k, (size_t)mr, (size_t)kr, (size_t)sr,
+                                        /*m_idx_start*/ 0, src_ptr, lhs_stride, dst_ptr);
 
-                    variant_call<void>(lhs_info->pack_func, num_m_per_thread, k, mr, kr, sr, 0, src_ptr, lhs_stride, dst_ptr);
+                        cur       += take;
+                        remaining -= take;
+                    }
                 }
             }
 
-            // RHS packing
-            if (first_to_arrive.test_and_set(std::memory_order_acquire) == false) {
-                // First thread to reach this point handles RHS packing
-                memset(bias, 0, n * sizeof(float));
-                transpose_f32kxn_f16nxk(n, k, reinterpret_cast<float *>(rhs_kxn),
-                                        reinterpret_cast<const uint16_t *>(rhs_batch), rhs_stride);
-
-                variant_call<void>(kernels->rhs_info.pack_func, 1, n, k, nr, kr, sr, n * sizeof(float),
-                             rhs_kxn, bias, nullptr, rhs_packed, 0, nullptr);
+            // RHS packing (single thread), then synchronize
+            if (ith == 0) {
+                memset(bias, 0, (size_t)n * sizeof(float));
+                transpose_f32kxn_f16nxk((size_t)n, (size_t)k,
+                                        reinterpret_cast<float *>(rhs_kxn),
+                                        reinterpret_cast<const uint16_t *>(rhs_batch_base),
+                                        rhs_stride);
+
+                variant_call<void>(kernels->rhs_info.pack_func,
+                                   /*num_groups*/ 1, (size_t)n, (size_t)k, (size_t)nr, (size_t)kr, (size_t)sr,
+                                   /*rhs_stride (bytes)*/ (size_t)(n * sizeof(float)),
+                                   rhs_kxn, bias, nullptr, rhs_packed, /*extra_bytes*/ 0, /*params*/ nullptr);
             }
 
             ggml_barrier(params->threadpool);
 
-            first_to_arrive.clear(std::memory_order_release);
-
-            // Perform the matmul
+            // Matmul (threaded over n)
             {
-                const int64_t m_to_process = m;
-                const int64_t m_start      = 0;
-
-                const int64_t n_step      = static_cast<int64_t>(kernel->get_n_step());
-                int64_t num_threads       = KAI_MIN(n / n_step, nth);
-                if (num_threads <= 0) {
-                    num_threads = 1;
+                const int64_t n_step  = (int64_t) kernel->get_n_step();
+                int64_t num_threads_n = KAI_MIN(n / n_step, nth);
+                if (num_threads_n <= 0) {
+                    num_threads_n = 1;
                 }
 
-                if (ith < num_threads) {
-                    const int64_t num_n_per_thread0   = round_down(n / num_threads, n_step);
-                    const int64_t num_n_per_threadN_1 = n - (num_threads - 1) * num_n_per_thread0;
+                if (ith < num_threads_n) {
+                    const int64_t num_n_per_thread0   = round_down((size_t)(n / num_threads_n), (size_t)n_step);
+                    const int64_t num_n_per_threadN_1 = n - (num_threads_n - 1) * num_n_per_thread0;
 
                     const int64_t n_start      = ith * num_n_per_thread0;
-                    const int64_t n_to_process = (ith == num_threads - 1) ? num_n_per_threadN_1 : num_n_per_thread0;
+                    const int64_t n_to_process = (ith == num_threads_n - 1) ? num_n_per_threadN_1 : num_n_per_thread0;
 
-                    const size_t lhs_packed_offset = variant_call<size_t>(kernel->get_lhs_offset, m_start, k);
-                    const size_t rhs_packed_offset = variant_call<size_t>(kernel->get_rhs_packed_offset, n_start, k);
-                    const size_t dst_offset        = kernel->get_dst_offset(m_start, n_start, dst_stride);
+                    // LHS packed base at row 0 (consistent with packing above)
+                    const size_t lhs_packed_offset0 = variant_call<size_t>(
+                        lhs_info->get_packed_offset, (size_t)0, (size_t)k, (size_t)mr, (size_t)kr, (size_t)sr);
+                    const size_t rhs_packed_offset = variant_call<size_t>(kernel->get_rhs_packed_offset, (size_t)n_start, (size_t)k);
+                    const size_t dst_offset        = kernel->get_dst_offset((size_t)0, (size_t)n_start, dst_stride);
 
-                    const void * lhs_ptr = lhs_packed + lhs_packed_offset;
+                    const void * lhs_ptr = lhs_packed + lhs_packed_offset0;
                     const void * rhs_ptr = rhs_packed + rhs_packed_offset;
-                    float * dst_ptr      = reinterpret_cast<float *>(dst_batch + dst_offset);
+                    float * dst_ptr      = reinterpret_cast<float *>(dst_batch_base + dst_offset);
 
-                    variant_call<void>(kernel->run_kernel, m_to_process, n_to_process, k, lhs_ptr, rhs_ptr, dst_ptr, dst_stride, sizeof(float), -FLT_MAX, FLT_MAX);
+                    variant_call<void>(kernel->run_kernel,
+                                       (size_t)m, (size_t)n_to_process, (size_t)k,
+                                       lhs_ptr, rhs_ptr,
+                                       dst_ptr, dst_stride, sizeof(float),
+                                       -FLT_MAX, FLT_MAX);
                 }
             }
 
             if (batch_idx != batch_size - 1) {
-                // This barrier is necessary when the batch size is larger than 1. While processing a batch,
-                // the work data buffer (params->wdata) is used as temporary storage which means that only
-                // a single batch can be processed at any given time. No barrier is needed for the last
-                // batch since GGML inserts a barrier between the execution of every operator.
                 ggml_barrier(params->threadpool);
             }
         }