[CK TILE] GEMM and Batched GEMM SplitK support (#1724)

* [CK TILE] Add split K support in GEMM

* Updates

* Fixes

* rebase

* fix

* Fix

* fixes

* support for batched gemm

example/ck_tile/03_gemm/gemm_basic.hpp

@@ -54,8 +54,7 @@ using CDataType   = Types::CDataType;
 auto create_args(int argc, char* argv[])
 {
     ck_tile::ArgParser arg_parser;
-    arg_parser.insert("b", "1", "batch size")
-        .insert("m", "3840", "m dimension")
+    arg_parser.insert("m", "3840", "m dimension")
         .insert("n", "4096", "n dimension")
         .insert("k", "2048", "k dimension")
         .insert("a_layout", "R", "A tensor data layout - Row by default")
@@ -68,7 +67,8 @@ auto create_args(int argc, char* argv[])
         .insert("prec", "fp16", "data type. fp16/bf16/fp8/bf8")
         .insert("warmup", "50", "number of iterations before benchmark the kernel")
         .insert("repeat", "100", "number of iterations to benchmark the kernel")
-        .insert("timer", "gpu", "gpu:gpu timer, cpu:cpu timer");
+        .insert("timer", "gpu", "gpu:gpu timer, cpu:cpu timer")
+        .insert("split_k", "1", "splitK value");
 
     bool result = arg_parser.parse(argc, argv);
     return std::make_tuple(result, arg_parser);

example/ck_tile/03_gemm/run_gemm_example.inc

@@ -64,9 +64,9 @@ int run_gemm_example_with_layouts(int argc,
     ck_tile::index_t stride_B = arg_parser.get_int("stride_b");
     ck_tile::index_t stride_C = arg_parser.get_int("stride_c");
 
-    ck_tile::index_t batch_size = arg_parser.get_int("b");
-    int n_warmup                = arg_parser.get_int("warmup");
-    int n_repeat                = arg_parser.get_int("repeat");
+    ck_tile::index_t kbatch = arg_parser.get_int("split_k");
+    int n_warmup            = arg_parser.get_int("warmup");
+    int n_repeat            = arg_parser.get_int("repeat");
 
     using namespace ck_tile::literals;
 
@@ -133,7 +133,7 @@ int run_gemm_example_with_layouts(int argc,
                                            stride_A,
                                            stride_B,
                                            stride_C,
-                                           batch_size,
+                                           kbatch,
                                            n_warmup,
                                            n_repeat);
 

example/ck_tile/03_gemm/universal_gemm.cpp

@@ -22,7 +22,7 @@
 #endif
 
 template <typename ALayout, typename BLayout, typename CLayout>
-float gemm_calc(const gemm_basic_args& args, const ck_tile::stream_config& s)
+float gemm_calc(const ck_tile::GemmHostArgs& args, const ck_tile::stream_config& s)
 {
 #if(CK_TILE_PIPELINE_DEFAULT == CK_TILE_PIPELINE_MEMORY)
     // Memory friendly for Interwave scheduler
@@ -78,7 +78,9 @@ float gemm_calc(const gemm_basic_args& args, const ck_tile::stream_config& s)
 #endif
         ck_tile::GemmPipelineProblem<ADataType, BDataType, AccDataType, GemmShape, Traits>>;
 
-    const ck_tile::index_t num_loop    = TilePartitioner::GetLoopNum(args.K);
+    const ck_tile::index_t k_grain     = args.k_batch * K_Tile;
+    const ck_tile::index_t K_split     = (args.K + k_grain - 1) / k_grain * K_Tile;
+    const ck_tile::index_t num_loop    = TilePartitioner::GetLoopNum(K_split);
     const bool has_hot_loop            = BaseGemmPipeline::BlockHasHotloop(num_loop);
     const ck_tile::TailNumber tail_num = BaseGemmPipeline::GetBlockLoopTailNum(num_loop);
 
@@ -106,17 +108,9 @@ float gemm_calc(const gemm_basic_args& args, const ck_tile::stream_config& s)
                                                   has_hot_loop_v,
                                                   tail_number_v>>;
         using Kernel = ck_tile::GemmKernel<TilePartitioner, GemmPipeline, GemmEpilogue>;
-        auto kargs   = Kernel::MakeKargs(args.p_a,
-                                       args.p_b,
-                                       args.p_c,
-                                       args.M,
-                                       args.N,
-                                       args.K,
-                                       args.stride_A,
-                                       args.stride_B,
-                                       args.stride_C);
-
-        const dim3 grids      = Kernel::GridSize(args.M, args.N, args.kbatch);
+        auto kargs   = Kernel::MakeKernelArgs(args);
+
+        const dim3 grids      = Kernel::GridSize(args.M, args.N, args.k_batch);
         constexpr dim3 blocks = Kernel::BlockSize();
 
         if(!Kernel::IsSupportedArgument(kargs))

example/ck_tile/16_batched_gemm/batched_gemm.cpp

@@ -70,20 +70,25 @@ float batched_gemm(const ck_tile::BatchedGemmHostArgs& args, const ck_tile::stre
 
     using CodegenGemmTraits =
         ck_tile::TileGemmTraits<kPadM, kPadN, kPadK, ALayout, BLayout, CLayout>;
-
     using CodegenPipelineProblem = ck_tile::
         GemmPipelineProblem<ADataType, BDataType, AccDataType, CodegenGemmShape, CodegenGemmTraits>;
-
-    using CodegenGemmPipeline = ck_tile::GemmPipelineAGmemBGmemCRegV1<CodegenPipelineProblem>;
+    using CodegenGemmPolicy = ck_tile::UniversalGemmPipelineAgBgCrPolicy;
+    using CodegenGemmPipeline =
+        ck_tile::GemmPipelineAGmemBGmemCRegV1<CodegenPipelineProblem, CodegenGemmPolicy>;
     // ToDo: Will add the codegen part to test different pipeline policies in GEMM.
     // Now we only use the BlockGemmASmemBSmemCRegV1DefaultPolicy.
     using Kernel = ck_tile::BatchedGemmKernel<TilePartitioner, CodegenGemmPipeline, GemmEpilogue>;
 
     auto kargs = Kernel::MakeKernelArgs(args);
 
-    const dim3 grids      = Kernel::GridSize(args.M, args.N, args.batch_count);
+    const dim3 grids      = Kernel::GridSize(args.M, args.N, args.k_batch, args.batch_count);
     constexpr dim3 blocks = Kernel::BlockSize();
 
+    if(!Kernel::IsSupportedArgument(kargs))
+    {
+        throw std::runtime_error("Wrong! Arguments not supported! Skipping gemm!\n");
+    }
+
     if(s.log_level_ > 0)
     {
         std::cout << "Launching kernel with args:"

example/ck_tile/16_batched_gemm/batched_gemm.hpp

@@ -49,7 +49,8 @@ auto create_args(int argc, char* argv[])
         .insert("prec", "fp16", "data type. fp16/bf16/fp8/bf8")
         .insert("warmup", "50", "number of iterations before benchmark the kernel")
         .insert("repeat", "100", "number of iterations to benchmark the kernel")
-        .insert("timer", "gpu", "gpu:gpu timer, cpu:cpu timer");
+        .insert("timer", "gpu", "gpu:gpu timer, cpu:cpu timer")
+        .insert("split_k", "1", "splitK value");
 
     bool result = arg_parser.parse(argc, argv);
     return std::make_tuple(result, arg_parser);

example/ck_tile/16_batched_gemm/run_batched_gemm_example.inc

@@ -17,6 +17,7 @@ float invoke_batched_gemm(ck_tile::DeviceMem& a_m_k_dev_buf,
                           ck_tile::index_t batch_stride_B,
                           ck_tile::index_t batch_stride_C,
                           ck_tile::index_t batch_count,
+                          ck_tile::index_t kbatch,
                           int n_warmup,
                           int n_repeat)
 {
@@ -24,6 +25,7 @@ float invoke_batched_gemm(ck_tile::DeviceMem& a_m_k_dev_buf,
     args.a_ptr          = a_m_k_dev_buf.GetDeviceBuffer();
     args.b_ptr          = b_k_n_dev_buf.GetDeviceBuffer();
     args.c_ptr          = c_m_n_dev_buf.GetDeviceBuffer();
+    args.k_batch        = kbatch;
     args.M              = M;
     args.N              = N;
     args.K              = K;
@@ -79,6 +81,7 @@ int run_batched_gemm_example_with_layouts(int argc,
     ck_tile::index_t batch_stride_B = arg_parser.get_int("batch_stride_b");
     ck_tile::index_t batch_stride_C = arg_parser.get_int("batch_stride_c");
     ck_tile::index_t batch_count    = arg_parser.get_int("batch_count");
+    ck_tile::index_t kbatch         = arg_parser.get_int("split_k");
 
     int n_warmup = arg_parser.get_int("warmup");
     int n_repeat = arg_parser.get_int("repeat");
@@ -159,6 +162,7 @@ int run_batched_gemm_example_with_layouts(int argc,
                                                    batch_stride_B,
                                                    batch_stride_C,
                                                    batch_count,
+                                                   kbatch,
                                                    n_warmup,
                                                    n_repeat);
 

include/ck_tile/ops/epilogue/cshuffle_epilogue.hpp

 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
+// Copyright (c) 2018-2024, Advanced Micro Devices, Inc. All rights reserved.
 
 #pragma once
 
@@ -56,6 +56,13 @@ struct CShuffleEpilogue
     // No additional shared memory needed
     CK_TILE_HOST_DEVICE static constexpr index_t GetSmemSize() { return 0; }
 
+    CK_TILE_HOST_DEVICE static constexpr bool IsOutputTransposed()
+    {
+        // TODO: At now CShuffle doesn't allow to vector store after permute.
+        //       It should be fixed and this function should return true.
+        return false;
+    }
+
     template <typename OAccTile>
     CK_TILE_DEVICE void permute_tile_data(OAccTile& o_acc_tile)
     {
@@ -111,7 +118,9 @@ struct CShuffleEpilogue
         }
     }
 
-    template <typename ODramWindowTmp, typename OAccTile>
+    template <typename ODramWindowTmp,
+              typename OAccTile,
+              memory_operation_enum out_memory_data_op = memory_operation_enum::set>
     CK_TILE_DEVICE auto operator()(ODramWindowTmp& o_dram_window_tmp, OAccTile& o_acc_tile)
     {
         const auto& current_window_origin = o_dram_window_tmp.get_window_origin();
@@ -158,12 +167,26 @@ struct CShuffleEpilogue
         // Store the tile data to the permuted location
         if constexpr(kPadM || kPadN)
         {
-            store_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            if constexpr(out_memory_data_op == memory_operation_enum::set)
+            {
+                store_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
+            else
+            {
+                update_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
             buffer_store_fence();
         }
         else
         {
-            store_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            if constexpr(out_memory_data_op == memory_operation_enum::set)
+            {
+                store_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
+            else
+            {
+                update_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
         }
     }
 };

include/ck_tile/ops/epilogue/default_2d_epilogue.hpp

 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
+// Copyright (c) 2018-2024, Advanced Micro Devices, Inc. All rights reserved.
 
 #pragma once
 
@@ -35,21 +35,39 @@ struct Default2DEpilogue
 
     CK_TILE_HOST_DEVICE static constexpr index_t GetSmemSize() { return 0; }
 
+    CK_TILE_HOST_DEVICE static constexpr bool IsOutputTransposed() { return false; }
+
     // TODO: this function assume store out vector size is the same as OAccTile last dimension size
     //       how do we fix this ?
-    template <typename ODramWindowTmp, typename OAccTile>
+    template <typename ODramWindowTmp,
+              typename OAccTile,
+              memory_operation_enum out_memory_data_op = memory_operation_enum::set>
     CK_TILE_DEVICE auto operator()(ODramWindowTmp& o_dram_window_tmp, const OAccTile& o_acc_tile)
     {
 
         // TODO: this is ugly
         if constexpr(UseRawStore && (kPadM || kPadN))
         {
-            store_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            if constexpr(out_memory_data_op == memory_operation_enum::set)
+            {
+                store_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
+            else
+            {
+                update_tile_raw(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
             buffer_store_fence();
         }
         else
         {
-            store_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            if constexpr(out_memory_data_op == memory_operation_enum::set)
+            {
+                store_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
+            else
+            {
+                update_tile(o_dram_window_tmp, cast_tile<ODataType>(o_acc_tile));
+            }
         }
     }
 };

include/ck_tile/ops/gemm/kernel/batched_gemm_kernel.hpp

@@ -67,9 +67,10 @@ struct BatchedGemmKernel : public GemmKernel<TilePartitioner_, GemmPipeline_, Ep
 
     using KernelArgs = BatchedGemmKernelArgs;
 
-    __host__ static constexpr auto GridSize(index_t M, index_t N, index_t batch_count)
+    __host__ static constexpr auto
+    GridSize(index_t M, index_t N, index_t KBatch, index_t batch_count)
     {
-        return TilePartitioner::GridSize(M, N, batch_count);
+        return TilePartitioner::GridSize(M, N, KBatch * batch_count);
     }
 
     __host__ static constexpr auto BlockSize() { return dim3(Base::KernelBlockSize); }
@@ -85,7 +86,8 @@ struct BatchedGemmKernel : public GemmKernel<TilePartitioner_, GemmPipeline_, Ep
                                       hostArgs.K,
                                       hostArgs.stride_A,
                                       hostArgs.stride_B,
-                                      hostArgs.stride_C},
+                                      hostArgs.stride_C,
+                                      hostArgs.k_batch},
                                      hostArgs.batch_stride_A,
                                      hostArgs.batch_stride_B,
                                      hostArgs.batch_stride_C,
@@ -100,22 +102,38 @@ struct BatchedGemmKernel : public GemmKernel<TilePartitioner_, GemmPipeline_, Ep
     CK_TILE_DEVICE void operator()(BatchedGemmKernelArgs kargs) const
     {
         const auto [i_m, i_n] = TilePartitioner{}();
-        const auto i_batch    = __builtin_amdgcn_readfirstlane(blockIdx.z);
+        const auto i_batch    = __builtin_amdgcn_readfirstlane(blockIdx.z / kargs.KBatch);
+        const auto i_k        = __builtin_amdgcn_readfirstlane(blockIdx.z - i_batch * kargs.KBatch);
+
+        const typename Base::SplitKBatchOffset splitk_batch_offset(kargs, i_k);
 
         //  options
         const auto batch_stride_A = __builtin_amdgcn_readfirstlane(kargs.batch_stride_A);
         const auto batch_offset_A = __builtin_amdgcn_readfirstlane(i_batch * batch_stride_A);
-        const ADataType* a_ptr    = static_cast<const ADataType*>(kargs.a_ptr) + batch_offset_A;
+        const ADataType* a_ptr    = static_cast<const ADataType*>(kargs.a_ptr) + batch_offset_A +
+                                 splitk_batch_offset.a_k_split_offset;
 
         const auto batch_stride_B = __builtin_amdgcn_readfirstlane(kargs.batch_stride_B);
         const auto batch_offset_B = __builtin_amdgcn_readfirstlane(i_batch * batch_stride_B);
-        const BDataType* b_ptr    = static_cast<const BDataType*>(kargs.b_ptr) + batch_offset_B;
+        const BDataType* b_ptr    = static_cast<const BDataType*>(kargs.b_ptr) + batch_offset_B +
+                                 splitk_batch_offset.b_k_split_offset;
 
         const auto batch_stride_C = __builtin_amdgcn_readfirstlane(kargs.batch_stride_C);
         const auto batch_offset_C = __builtin_amdgcn_readfirstlane(i_batch * batch_stride_C);
         CDataType* c_ptr          = static_cast<CDataType*>(kargs.c_ptr) + batch_offset_C;
 
-        this->RunGemm(a_ptr, b_ptr, c_ptr, kargs, i_m, i_n);
+        // allocate LDS
+        __shared__ char smem_ptr[GetSmemSize()];
+
+        if(kargs.KBatch == 1)
+        {
+            this->RunGemm(a_ptr, b_ptr, c_ptr, smem_ptr, kargs, splitk_batch_offset, i_m, i_n);
+        }
+        else
+        {
+            this->template RunGemm<memory_operation_enum::atomic_add>(
+                a_ptr, b_ptr, c_ptr, smem_ptr, kargs, splitk_batch_offset, i_m, i_n);
+        }
     }
 };
 

include/ck_tile/ops/gemm/kernel/gemm_kernel.hpp

@@ -93,6 +93,7 @@ struct GemmKernel
         index_t stride_A;
         index_t stride_B;
         index_t stride_C;
+        index_t KBatch;
     };
 
     CK_TILE_HOST static constexpr GemmKernelArgs MakeKernelArgs(const GemmHostArgs& hostArgs)
@@ -105,28 +106,72 @@ struct GemmKernel
                               hostArgs.K,
                               hostArgs.stride_A,
                               hostArgs.stride_B,
-                              hostArgs.stride_C};
+                              hostArgs.stride_C,
+                              hostArgs.k_batch};
     }
-    // CK_TILE_HOST static constexpr GemmKernelArgs MakeKernelArgs(const void* a_ptr,
-    //                                                             const void* b_ptr,
-    //                                                             void* c_ptr,
-    //                                                             index_t M,
-    //                                                             index_t N,
-    //                                                             index_t K,
-    //                                                             index_t stride_A,
-    //                                                             index_t stride_B,
-    //                                                             index_t stride_C)
-    // {
-    //     return GemmKernelArgs{a_ptr, b_ptr, c_ptr, M, N, K, stride_A, stride_B, stride_C};
-    // }
 
     CK_TILE_HOST_DEVICE static constexpr index_t GetSmemSize()
     {
         return max(GemmPipeline::GetSmemSize(), EpiloguePipeline::GetSmemSize());
     }
 
+    struct SplitKBatchOffset
+    {
+        __device__ SplitKBatchOffset(const GemmKernelArgs& kargs,
+                                     const std::size_t k_id = blockIdx.z)
+        {
+            constexpr auto K1   = TilePartitioner::BlockGemmShape::WarpTile::at(number<2>{});
+            const index_t K_t   = kargs.KBatch * K1;
+            const index_t KRead = (kargs.K + K_t - 1) / K_t * K1;
+
+            if constexpr(std::is_same_v<tensor_layout::gemm::RowMajor, ALayout>)
+            {
+                a_k_split_offset = k_id * KRead;
+            }
+            else if constexpr(std::is_same_v<tensor_layout::gemm::ColumnMajor, ALayout>)
+            {
+                a_k_split_offset = k_id * KRead * kargs.stride_A;
+            }
+
+            if constexpr(std::is_same_v<tensor_layout::gemm::RowMajor, BLayout>)
+            {
+                b_k_split_offset = k_id * KRead * kargs.stride_B;
+            }
+            else if constexpr(std::is_same_v<tensor_layout::gemm::ColumnMajor, BLayout>)
+            {
+                b_k_split_offset = k_id * KRead;
+            }
+
+            if(k_id < static_cast<uint32_t>(kargs.KBatch - 1))
+            {
+                splitted_k = KRead;
+            }
+            else
+            {
+                splitted_k = kargs.K - KRead * (kargs.KBatch - 1);
+            }
+        }
+
+        index_t a_k_split_offset;
+        index_t b_k_split_offset;
+        index_t splitted_k;
+    };
+
     CK_TILE_HOST static bool IsSupportedArgument(const GemmKernelArgs& kargs)
     {
+        constexpr bool is_output_c_reg_transposed =
+            EpiloguePipeline::IsOutputTransposed() != GemmPipeline::IsTransposeC();
+        if constexpr(!((GemmPipeline::VectorSizeC % 2 == 0 &&
+                        std::is_same_v<CLayout, tensor_layout::gemm::RowMajor> &&
+                        is_output_c_reg_transposed) ||
+                       !(std::is_same_v<CDataType, fp16_t> || std::is_same_v<CDataType, bf16_t>)))
+        {
+            if(kargs.KBatch != 1)
+            {
+                return false;
+            }
+        }
+
         if constexpr(std::is_same_v<ALayout, tensor_layout::gemm::RowMajor>)
         {
             if(kargs.K % TilePartitioner::kK != 0 && GemmPipeline::kPadK == false)
@@ -198,17 +243,19 @@ struct GemmKernel
         return true;
     }
 
-    CK_TILE_DEVICE auto MakeGemmTensorViews(const ADataType* a_ptr,
-                                            const BDataType* b_ptr,
-                                            CDataType* c_ptr,
-                                            const GemmKernelArgs& kargs) const
+    template <memory_operation_enum DstInMemOp = memory_operation_enum::set>
+    CK_TILE_DEVICE static auto MakeGemmTensorViews(const ADataType* a_ptr,
+                                                   const BDataType* b_ptr,
+                                                   CDataType* c_ptr,
+                                                   const GemmKernelArgs& kargs,
+                                                   const SplitKBatchOffset& splitk_batch_offset)
     {
         const auto& a_tensor_view = [&]() {
             if constexpr(std::is_same_v<ALayout, tensor_layout::gemm::RowMajor>)
             {
                 return make_naive_tensor_view<address_space_enum::global>(
                     a_ptr,
-                    make_tuple(kargs.M, kargs.K),
+                    make_tuple(kargs.M, splitk_batch_offset.splitted_k),
                     make_tuple(kargs.stride_A, 1),
                     number<GemmPipeline::VectorSizeA>{},
                     number<1>{});
@@ -217,7 +264,7 @@ struct GemmKernel
             {
                 return make_naive_tensor_view<address_space_enum::global>(
                     a_ptr,
-                    make_tuple(kargs.M, kargs.K),
+                    make_tuple(kargs.M, splitk_batch_offset.splitted_k),
                     make_tuple(1, kargs.stride_A),
                     number<1>{},
                     number<1>{});
@@ -229,7 +276,7 @@ struct GemmKernel
             {
                 return make_naive_tensor_view<address_space_enum::global>(
                     b_ptr,
-                    make_tuple(kargs.N, kargs.K),
+                    make_tuple(kargs.N, splitk_batch_offset.splitted_k),
                     make_tuple(1, kargs.stride_B),
                     number<1>{},
                     number<1>{});
@@ -238,7 +285,7 @@ struct GemmKernel
             {
                 return make_naive_tensor_view<address_space_enum::global>(
                     b_ptr,
-                    make_tuple(kargs.N, kargs.K),
+                    make_tuple(kargs.N, splitk_batch_offset.splitted_k),
                     make_tuple(kargs.stride_B, 1),
                     number<GemmPipeline::VectorSizeB>{},
                     number<1>{});
@@ -248,7 +295,7 @@ struct GemmKernel
         const auto& c_tensor_view = [&]() {
             if constexpr(std::is_same_v<CLayout, tensor_layout::gemm::RowMajor>)
             {
-                return make_naive_tensor_view<address_space_enum::global>(
+                return make_naive_tensor_view<address_space_enum::global, DstInMemOp>(
                     c_ptr,
                     make_tuple(kargs.M, kargs.N),
                     make_tuple(kargs.stride_C, 1),
@@ -257,7 +304,7 @@ struct GemmKernel
             }
             else
             {
-                return make_naive_tensor_view<address_space_enum::global>(
+                return make_naive_tensor_view<address_space_enum::global, DstInMemOp>(
                     c_ptr,
                     make_tuple(kargs.M, kargs.N),
                     make_tuple(1, kargs.stride_C),
@@ -270,7 +317,7 @@ struct GemmKernel
     }
 
     template <typename TensorView>
-    CK_TILE_DEVICE auto MakeGemmPadViews(const TensorView& views) const
+    CK_TILE_DEVICE static auto MakeGemmPadViews(const TensorView& views)
     {
         const auto& a_pad_view = [&]() {
             const auto& a_tensor_view = views.at(I0);
@@ -330,8 +377,8 @@ struct GemmKernel
     }
 
     template <typename PadView>
-    CK_TILE_DEVICE auto
-    MakeGemmTileWindows(const PadView& views, const index_t i_m, const index_t i_n) const
+    CK_TILE_DEVICE static auto
+    MakeGemmTileWindows(const PadView& views, const index_t i_m, const index_t i_n)
     {
         const auto& a_pad_view     = views.at(I0);
         const auto& a_block_window = make_tile_window(
@@ -363,23 +410,27 @@ struct GemmKernel
      * @param kargs GEMM kernel arguments
      * @param block_idx_m The GEMM's output M dimension tile index processed by this workgroup.
      * @param block_idx_n The GEMM's output N dimension tile index processed by this workgroup.
+     *
+     * @tparam DstInMemOp Destination memory operation (default: set).
      */
-    CK_TILE_DEVICE void RunGemm(const ADataType* a_ptr,
-                                const BDataType* b_ptr,
-                                CDataType* c_ptr,
-                                const GemmKernelArgs& kargs,
-                                const index_t block_idx_m,
-                                const index_t block_idx_n) const
+    template <memory_operation_enum DstInMemOp = memory_operation_enum::set>
+    CK_TILE_DEVICE static void RunGemm(const ADataType* a_ptr,
+                                       const BDataType* b_ptr,
+                                       CDataType* c_ptr,
+                                       void* smem_ptr,
+                                       const GemmKernelArgs& kargs,
+                                       const SplitKBatchOffset& splitk_batch_offset,
+                                       const index_t block_idx_m,
+                                       const index_t block_idx_n)
     {
         // Create Gemm tensor views, pad views and tile windows
-        const auto& gemm_tensor_views_tuple = MakeGemmTensorViews(a_ptr, b_ptr, c_ptr, kargs);
-        const auto& gemm_pad_views          = MakeGemmPadViews(gemm_tensor_views_tuple);
-        auto gemm_tile_windows = MakeGemmTileWindows(gemm_pad_views, block_idx_m, block_idx_n);
-
-        // allocate LDS
-        __shared__ char smem_ptr[GetSmemSize()];
+        const auto& gemm_tensor_views_tuple =
+            MakeGemmTensorViews<DstInMemOp>(a_ptr, b_ptr, c_ptr, kargs, splitk_batch_offset);
+        ;
+        const auto& gemm_pad_views = MakeGemmPadViews(gemm_tensor_views_tuple);
+        auto gemm_tile_windows     = MakeGemmTileWindows(gemm_pad_views, block_idx_m, block_idx_n);
 
-        const index_t num_loop = TilePartitioner::GetLoopNum(kargs.K);
+        const index_t num_loop = TilePartitioner::GetLoopNum(splitk_batch_offset.splitted_k);
 
         // Run GEMM cooperatively by whole workgroup.
         const auto& a_block_window = gemm_tile_windows.at(I0);
@@ -389,18 +440,43 @@ struct GemmKernel
 
         // Run Epilogue Pipeline
         auto& c_block_window = gemm_tile_windows.at(I2);
-        EpiloguePipeline{}(c_block_window, c_block_tile);
+
+        constexpr bool is_output_c_reg_transposed =
+            EpiloguePipeline::IsOutputTransposed() != GemmPipeline::IsTransposeC();
+        if constexpr((DstInMemOp == memory_operation_enum::set) || (sizeof(CDataType) > 2) ||
+                     (GemmPipeline::VectorSizeC % 2 == 0 &&
+                      std::is_same_v<CLayout, tensor_layout::gemm::RowMajor> &&
+                      is_output_c_reg_transposed))
+        {
+            EpiloguePipeline{}
+                .template operator()<decltype(c_block_window), decltype(c_block_tile), DstInMemOp>(
+                    c_block_window, c_block_tile);
+        }
     }
 
     CK_TILE_DEVICE void operator()(GemmKernelArgs kargs) const
     {
         const auto [i_m, i_n] = TilePartitioner{}();
+        const SplitKBatchOffset splitk_batch_offset(kargs);
         // options
-        const ADataType* a_ptr = static_cast<const ADataType*>(kargs.a_ptr);
-        const BDataType* b_ptr = static_cast<const BDataType*>(kargs.b_ptr);
-        CDataType* c_ptr       = static_cast<CDataType*>(kargs.c_ptr);
+        const ADataType* a_ptr =
+            static_cast<const ADataType*>(kargs.a_ptr) + splitk_batch_offset.a_k_split_offset;
+        const BDataType* b_ptr =
+            static_cast<const BDataType*>(kargs.b_ptr) + splitk_batch_offset.b_k_split_offset;
+        CDataType* c_ptr = static_cast<CDataType*>(kargs.c_ptr);
+
+        // allocate LDS
+        __shared__ char smem_ptr[GetSmemSize()];
 
-        RunGemm(a_ptr, b_ptr, c_ptr, kargs, i_m, i_n);
+        if(kargs.KBatch == 1)
+        {
+            RunGemm(a_ptr, b_ptr, c_ptr, smem_ptr, kargs, splitk_batch_offset, i_m, i_n);
+        }
+        else
+        {
+            RunGemm<memory_operation_enum::atomic_add>(
+                a_ptr, b_ptr, c_ptr, smem_ptr, kargs, splitk_batch_offset, i_m, i_n);
+        }
     }
 };
 

include/ck_tile/ops/gemm/pipeline/gemm_pipeline_ag_bg_cr_comp_v3.hpp

@@ -82,6 +82,8 @@ struct GemmPipelineAgBgCrCompV3 : public BaseGemmPipelineAgBgCrCompV3<Problem>
         return Policy::template GetSmemSize<Problem>();
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return Policy::IsTransposeC(); }
+
     template <GemmPipelineScheduler Scheduler>
     struct PipelineImpl : public PipelineImplBase
     {

include/ck_tile/ops/gemm/pipeline/gemm_pipeline_ag_bg_cr_mem.hpp

@@ -132,6 +132,8 @@ struct GemmPipelineAgBgCrMem : public BaseGemmPipelineAgBgCrMem<Problem>
         return Policy::template GetSmemSize<Problem>();
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return Policy::IsTransposeC(); }
+
     template <GemmPipelineScheduler Scheduler>
     struct PipelineImpl : public PipelineImplBase
     {

include/ck_tile/ops/gemm/pipeline/gemm_pipeline_agmem_bgmem_creg_v1.hpp

@@ -53,6 +53,8 @@ struct GemmPipelineAGmemBGmemCRegV1
         return Policy::template GetSmemSize<Problem>();
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return Policy::IsTransposeC(); }
+
     template <typename ADramBlockWindowTmp,
               typename BDramBlockWindowTmp,
               typename AElementFunction,

include/ck_tile/ops/gemm/pipeline/gemm_pipeline_agmem_bgmem_creg_v1_default_policy.hpp

@@ -13,6 +13,8 @@ namespace ck_tile {
 struct GemmPipelineAGmemBGmemCRegV1DefaultPolicy
 {
 
+    static constexpr bool TransposeC = false;
+
 #if 0
     // 2d
     template <typename Problem>
@@ -114,8 +116,7 @@ struct GemmPipelineAGmemBGmemCRegV1DefaultPolicy
     {
         constexpr index_t smem_size_a = GetSmemSizeA<Problem>();
         constexpr index_t smem_size_b = GetSmemSizeB<Problem>();
-        index_t smem_size             = 0;
-        smem_size += smem_size_a + smem_size_b;
+        constexpr index_t smem_size   = smem_size_a + smem_size_b;
 
         return smem_size;
     }
@@ -485,13 +486,14 @@ struct GemmPipelineAGmemBGmemCRegV1DefaultPolicy
         }
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return TransposeC; }
+
     template <typename Problem>
     CK_TILE_HOST_DEVICE static constexpr auto GetBlockGemm()
     {
-        constexpr bool TransposeC = false;
-        constexpr auto I0         = number<0>{};
-        constexpr auto I1         = number<1>{};
-        constexpr auto I2         = number<2>{};
+        constexpr auto I0 = number<0>{};
+        constexpr auto I1 = number<1>{};
+        constexpr auto I2 = number<2>{};
 
         using AccDataType     = float;
         using BlockWarps      = typename Problem::BlockGemmShape::BlockWarps;

include/ck_tile/ops/gemm/pipeline/gemm_pipeline_agmem_bgmem_creg_v2.hpp

@@ -36,6 +36,8 @@ struct GemmPipelineAGmemBGmemCRegV2
                    Policy::template MakeBLdsBlockDescriptor<Problem>().get_element_space_size();
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return Policy::IsTransposeC(); }
+
     template <typename ADramBlockWindowTmp,
               typename BDramBlockWindowTmp,
               typename AElementFunction,

include/ck_tile/ops/gemm/pipeline/gemm_universal_pipeline_ag_bg_cr_policy.hpp

@@ -444,6 +444,8 @@ struct UniversalGemmPipelineAgBgCrPolicy
         }
     }
 
+    CK_TILE_HOST_DEVICE static constexpr auto IsTransposeC() { return TransposeC; }
+
     template <typename Problem>
     CK_TILE_HOST_DEVICE static constexpr auto GetBlockGemm()
     {

test/ck_tile/batched_gemm/test_batched_gemm_util.hpp

@@ -93,7 +93,7 @@ class TestCkTileBatchedGemm : public ::testing::Test
 
         auto kargs = Kernel::MakeKernelArgs(args);
 
-        const dim3 grids      = Kernel::GridSize(args.M, args.N, args.batch_count);
+        const dim3 grids      = Kernel::GridSize(args.M, args.N, args.k_batch, args.batch_count);
         constexpr dim3 blocks = Kernel::BlockSize();
 
         if(s.log_level_ > 0)
@@ -186,6 +186,7 @@ class TestCkTileBatchedGemm : public ::testing::Test
         args.a_ptr          = a_m_k_dev_buf.GetDeviceBuffer();
         args.b_ptr          = b_k_n_dev_buf.GetDeviceBuffer();
         args.c_ptr          = c_m_n_dev_buf.GetDeviceBuffer();
+        args.k_batch        = 1;
         args.M              = M;
         args.N              = N;
         args.K              = K;

test/ck_tile/gemm/test_gemm_pipeline_util.hpp

@@ -74,7 +74,9 @@ class TestCkTileGemmPipeline : public ::testing::Test
                 ck_tile::
                     GemmPipelineProblem<ADataType, BDataType, AccDataType, GemmShape, Traits>>>;
 
-        const ck_tile::index_t num_loop    = TilePartitioner::GetLoopNum(args.K);
+        const ck_tile::index_t k_grain     = args.k_batch * K_Tile;
+        const ck_tile::index_t K_split     = (args.K + k_grain - 1) / k_grain * K_Tile;
+        const ck_tile::index_t num_loop    = TilePartitioner::GetLoopNum(K_split);
         const bool has_hot_loop            = BaseGemmPipeline::BlockHasHotloop(num_loop);
         const ck_tile::TailNumber tail_num = BaseGemmPipeline::GetBlockLoopTailNum(num_loop);