Ck tile/layernorm: implement naive reduce, opt performance (#1784)

* add no welford

* enable output raw

* raw of int8

* fix build

* fix smoke test err

* [ck_tile]layernorm: fix welford ok, set int8 and bf16 small N as default and others open by generate

* [cktile]layernorm, fix err commit files and remove uselss

* fix quant 8192 err & change norm_reduce class and file name

---------
Co-authored-by: coderfeli <coderfeli@163.com>
Co-authored-by: carlushuang <carlus.huang@amd.com>

example/ck_tile/02_layernorm2d/script/smoke_test.sh

@@ -27,7 +27,8 @@ $EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=7   -n=2734
 $EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=1   -n=3182
 $EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=9   -n=4096
 $EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=3   -n=8192
-#$EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=1   -n=10547
+$EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=3   -n=9120
+$EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=1   -n=10547
 #$EXE -prec_i=$pr_i -fadd=$fadd $fquant -m=3   -n=17134
 done
 done

include/ck_tile/ops/layernorm2d/pipeline/layernorm2d_fwd_pipeline_default_policy.hpp

@@ -4,8 +4,8 @@
 #pragma once
 
 #include "ck_tile/core.hpp"
-#include "ck_tile/ops/welford/block/block_welford_problem.hpp"
-#include "ck_tile/ops/welford/block/block_welford.hpp"
+#include "ck_tile/ops/norm_reduce/block/block_norm_reduce_problem.hpp"
+#include "ck_tile/ops/norm_reduce/block/block_norm_reduce.hpp"
 
 namespace ck_tile {
 
@@ -43,36 +43,38 @@ struct Layernorm2dFwdPipelineDefaultPolicy
     }
 
     template <typename Problem>
-    CK_TILE_HOST_DEVICE static constexpr auto GetBlockWelford()
+    CK_TILE_HOST_DEVICE static constexpr auto GetBlockNormReduce()
     {
-        using P_ = BlockWelfordProblem<typename Problem::ComputeDataType,
-                                       typename Problem::ComputeDataType,
-                                       typename Problem::BlockShape,
-                                       Problem::Traits::kFastFDiv>;
-
-        return BlockWelford<P_>{};
+        using P_ = BlockNormReduceProblem<typename Problem::ComputeDataType,
+                                          typename Problem::ComputeDataType,
+                                          typename Problem::BlockShape,
+                                          Problem::Traits::kFastFDiv,
+                                          Problem::Traits::kWelford>;
+        return BlockNormReduce<P_>{};
     }
 
     template <typename Problem>
-    CK_TILE_HOST_DEVICE static constexpr auto GetBlockWelfordSync()
+    CK_TILE_HOST_DEVICE static constexpr auto GetBlockNormReduceSync()
     {
-        using P_ = BlockWelfordProblem<typename Problem::ComputeDataType,
-                                       typename Problem::ComputeDataType,
-                                       typename Problem::BlockShape,
-                                       Problem::Traits::kFastFDiv>;
+        using P_ = BlockNormReduceProblem<typename Problem::ComputeDataType,
+                                          typename Problem::ComputeDataType,
+                                          typename Problem::BlockShape,
+                                          Problem::Traits::kFastFDiv,
+                                          Problem::Traits::kWelford>;
 
-        return BlockWelfordSync<P_>{};
+        return BlockNormReduceSync<P_>{};
     }
 
     template <typename Problem>
-    CK_TILE_HOST_DEVICE static constexpr auto GetBlockWelfordCrossWarpSync()
+    CK_TILE_HOST_DEVICE static constexpr auto GetBlockNormReduceCrossWarpSync()
     {
-        using P_ = BlockWelfordProblem<typename Problem::ComputeDataType,
-                                       typename Problem::ComputeDataType,
-                                       typename Problem::BlockShape,
-                                       Problem::Traits::kFastFDiv>;
+        using P_ = BlockNormReduceProblem<typename Problem::ComputeDataType,
+                                          typename Problem::ComputeDataType,
+                                          typename Problem::BlockShape,
+                                          Problem::Traits::kFastFDiv,
+                                          Problem::Traits::kWelford>;
 
-        return BlockWelfordCrossWarpSync<P_>{};
+        return BlockNormReduceCrossWarpSync<P_>{};
     }
 
     template <typename Problem>
@@ -80,19 +82,20 @@ struct Layernorm2dFwdPipelineDefaultPolicy
     {
         if constexpr(Problem::kNeedCrossWarpSync)
         {
-            using P_ = BlockWelfordProblem<typename Problem::ComputeDataType,
-                                           typename Problem::ComputeDataType,
-                                           typename Problem::BlockShape,
-                                           Problem::Traits::kFastFDiv>;
+            using P_ = BlockNormReduceProblem<typename Problem::ComputeDataType,
+                                              typename Problem::ComputeDataType,
+                                              typename Problem::BlockShape,
+                                              Problem::Traits::kFastFDiv,
+                                              Problem::Traits::kWelford>;
 
-            using block_welford = BlockWelford<P_>;
+            using block_welford = BlockNormReduce<P_>;
             using x_block_tile =
                 decltype(make_static_distributed_tensor<typename Problem::ComputeDataType>(
                     MakeXBlockTileDistribution<Problem>()));
             using mean_var_block_tile =
                 decltype(block_welford::template MakeMeanVarBlockTile<x_block_tile>());
 
-            return GetBlockWelfordCrossWarpSync<Problem>()
+            return GetBlockNormReduceCrossWarpSync<Problem>()
                 .template GetSmemSize<mean_var_block_tile>();
         }
         else

include/ck_tile/ops/layernorm2d/pipeline/layernorm2d_fwd_pipeline_one_pass.hpp

@@ -37,6 +37,7 @@ struct Layernorm2dFwdPipelineOnePass
     static constexpr bool kPadM              = false; // TODO - BlockLayernorm2dFwdProblem::kPadM
     static constexpr bool kPadN              = Problem::Traits::kPadN;
     static constexpr bool kFastFDiv          = Problem::Traits::kFastFDiv;
+    static constexpr bool kWelford           = Problem::Traits::kWelford;
     static constexpr auto kFusedAdd          = Problem::Traits::kFusedAdd;
     static constexpr auto kFusedQuant        = Problem::Traits::kFusedQuant;
 
@@ -95,11 +96,16 @@ struct Layernorm2dFwdPipelineOnePass
         int cur_count = 0;
         int max_count =
             block_tile_welford_calculate_max_count<typename Problem::BlockShape>(row_size);
-        auto block_welford      = Policy::template GetBlockWelford<Problem>();
-        auto block_welford_sync = Policy::template GetBlockWelfordSync<Problem>();
-        auto block_welford_cross_warp_sync =
-            Policy::template GetBlockWelfordCrossWarpSync<Problem>();
-
+        auto block_norm_reduce      = Policy::template GetBlockNormReduce<Problem>();
+        auto block_norm_reduce_sync = Policy::template GetBlockNormReduceSync<Problem>();
+        auto block_norm_reduce_cross_warp_sync =
+            Policy::template GetBlockNormReduceCrossWarpSync<Problem>();
+
+        using XTensorType = decltype(cast_tile<ComputeDataType>(x));
+        auto mean         = block_norm_reduce.template MakeMeanVarBlockTile<XTensorType>();
+        auto var          = block_norm_reduce.template MakeMeanVarBlockTile<XTensorType>();
+        clear_tile(mean);
+        clear_tile(var);
         // load gamma/beta (TODO: support no gamma/beta?)
         const auto gamma = load_tile(gamma_window);
         const auto beta  = load_tile(beta_window);
@@ -117,12 +123,21 @@ struct Layernorm2dFwdPipelineOnePass
                 store_tile(y_residual_window, cast_tile<YResidualDataType>(acc));
         }
 
-        // compute welford each-thread->cross-lane->cross-warp
-        auto [mean, var] = block_welford(acc, cur_count, max_count);
-        block_welford_sync(mean, var, cur_count);
-        block_welford_cross_warp_sync(mean, var, cur_count, smem);
-        block_tile_welford_post_scale_var(var, cur_count, constant<kFastFDiv>{});
-
+        // compute reduce each-thread->cross-lane->cross-warp
+        block_norm_reduce(acc, mean, var, cur_count, max_count);
+        block_norm_reduce_sync(mean, var, cur_count);
+        block_norm_reduce_cross_warp_sync(mean, var, cur_count, smem);
+        if(kWelford)
+        {
+            block_tile_welford_post_scale_var(var, cur_count, constant<kFastFDiv>{});
+        }
+        else
+        {
+            sweep_tile(mean, [&](auto idx) {
+                mean(idx) = mean(idx) / type_convert<MeanDataType>(row_size);
+                var(idx)  = var(idx) / type_convert<MeanDataType>(row_size) - mean(idx) * mean(idx);
+            });
+        }
         // compute inv-std
         auto inv_std = tile_elementwise_in(
             [&](const auto& v_) {
@@ -153,8 +168,7 @@ struct Layernorm2dFwdPipelineOnePass
             const auto beta_  = type_convert<ComputeDataType>(beta[j_idx]);
 
             auto ln_ = (acc[idx] - mean_[i_idx]) * inv_std[i_idx] * gamma_ + beta_;
-
-            ln(idx) = ln_;
+            ln(idx)  = ln_;
         });
 
         if constexpr(kFusedQuant == Layernorm2dFusedQuantEnum::DYNAMIC_QUANT ||

include/ck_tile/ops/layernorm2d/pipeline/layernorm2d_fwd_pipeline_two_pass.hpp

@@ -36,6 +36,7 @@ struct Layernorm2dFwdPipelineTwoPass
     static constexpr bool kPadM              = false; // TODO - BlockLayernorm2dFwdProblem::kPadM
     static constexpr bool kPadN              = Problem::Traits::kPadN;
     static constexpr bool kFastFDiv          = Problem::Traits::kFastFDiv;
+    static constexpr bool kWelford           = Problem::Traits::kWelford;
     static constexpr auto kFusedAdd          = Problem::Traits::kFusedAdd;
     static constexpr auto kFusedQuant        = Problem::Traits::kFusedQuant;
 
@@ -77,6 +78,7 @@ struct Layernorm2dFwdPipelineTwoPass
                                    void* smem,
                                    Epilogue) const
     {
+        static_assert(kWelford == true, "2 pass only supports welford merge");
         auto x_window =
             make_tile_window(x_window_, Policy::template MakeXBlockTileDistribution<Problem>());
         auto gamma_window = make_tile_window(
@@ -102,14 +104,14 @@ struct Layernorm2dFwdPipelineTwoPass
         int max_count =
             (num_n_tile_iteration - 1) * count_per_iter +
             block_tile_welford_calculate_max_count<typename Problem::BlockShape>(last_iter_n);
-        auto block_welford      = Policy::template GetBlockWelford<Problem>();
-        auto block_welford_sync = Policy::template GetBlockWelfordSync<Problem>();
-        auto block_welford_cross_warp_sync =
-            Policy::template GetBlockWelfordCrossWarpSync<Problem>();
+        auto block_norm_reduce      = Policy::template GetBlockNormReduce<Problem>();
+        auto block_norm_reduce_sync = Policy::template GetBlockNormReduceSync<Problem>();
+        auto block_norm_reduce_cross_warp_sync =
+            Policy::template GetBlockNormReduceCrossWarpSync<Problem>();
 
         using XTensorType = decltype(cast_tile<ComputeDataType>(load_tile(x_window)));
-        auto mean         = block_welford.template MakeMeanVarBlockTile<XTensorType>();
-        auto var          = block_welford.template MakeMeanVarBlockTile<XTensorType>();
+        auto mean         = block_norm_reduce.template MakeMeanVarBlockTile<XTensorType>();
+        auto var          = block_norm_reduce.template MakeMeanVarBlockTile<XTensorType>();
 
         for(int iN = __builtin_amdgcn_readfirstlane(0); iN < num_n_tile_iteration; ++iN)
         {
@@ -133,11 +135,11 @@ struct Layernorm2dFwdPipelineTwoPass
                     move_tile_window(y_residual_window, {0, Block_N});
                 }
             }
-            block_welford(acc, mean, var, cur_count, max_count);
+            block_norm_reduce(acc, mean, var, cur_count, max_count);
         }
 
-        block_welford_sync(mean, var, cur_count);
-        block_welford_cross_warp_sync(mean, var, cur_count, smem);
+        block_norm_reduce_sync(mean, var, cur_count);
+        block_norm_reduce_cross_warp_sync(mean, var, cur_count, smem);
         block_tile_welford_post_scale_var(var, cur_count, constant<kFastFDiv>{});
 
         // compute inv-std

include/ck_tile/ops/layernorm2d/pipeline/layernorm2d_fwd_traits.hpp

@@ -40,6 +40,7 @@ template<> struct Layernorm2dFusedQuantEnumName<Layernorm2dFusedQuantEnum::SMOOT
 template <bool kPadN_,
           bool kSaveMeanInvStd_,
           bool kFastFDiv_,
+          bool kWelford_,
           bool kTwoPass_,
           Layernorm2dFusedAddEnum kFusedAdd_,
           Layernorm2dFusedQuantEnum kFusedQuant_>
@@ -48,6 +49,7 @@ struct Layernorm2dFwdTraits
     static constexpr bool kPadN                            = kPadN_;
     static constexpr bool kSaveMeanInvStd                  = kSaveMeanInvStd_;
     static constexpr bool kFastFDiv                        = kFastFDiv_;
+    static constexpr bool kWelford                         = kWelford_;
     static constexpr bool kTwoPass                         = kTwoPass_;
     static constexpr Layernorm2dFusedAddEnum kFusedAdd     = kFusedAdd_;
     static constexpr Layernorm2dFusedQuantEnum kFusedQuant = kFusedQuant_;

include/ck_tile/ops/welford.hpp → include/ck_tile/ops/norm_reduce.hpp

@@ -3,8 +3,8 @@
 
 #pragma once
 
-#include "ck_tile/ops/welford/block/block_welford.hpp"
-#include "ck_tile/ops/welford/block/block_welford_problem.hpp"
-#include "ck_tile/ops/welford/thread/thread_welford.hpp"
+#include "ck_tile/ops/norm_reduce/block/block_norm_reduce.hpp"
+#include "ck_tile/ops/norm_reduce/block/block_norm_reduce_problem.hpp"
+#include "ck_tile/ops/norm_reduce/thread/thread_welford.hpp"
 #include "ck_tile/ops/common/generic_2d_block_shape.hpp"
 #include "ck_tile/ops/common/tensor_layout.hpp"

include/ck_tile/ops/welford/block/block_welford.hpp → include/ck_tile/ops/norm_reduce/block/block_norm_reduce.hpp

@@ -4,22 +4,23 @@
 #pragma once
 
 #include "ck_tile/core.hpp"
-#include "ck_tile/ops/welford/thread/thread_welford.hpp"
+#include "ck_tile/ops/norm_reduce/thread/thread_welford.hpp"
 
 namespace ck_tile {
 
 template <typename Problem_, typename Policy_ = void>
-struct BlockWelford
+struct BlockNormReduce
 {
     using Problem                   = remove_cvref_t<Problem_>;
     using XDataType                 = typename Problem::XDataType;
     using ComputeDataType           = typename Problem::ComputeDataType;
     static constexpr bool kFastFDiv = Problem::kFastFDiv;
+    static constexpr bool kWelford  = Problem::kWelford;
 
-    CK_TILE_DEVICE constexpr BlockWelford() {}
+    CK_TILE_DEVICE constexpr BlockNormReduce() {}
 
     // [CAUSION] - max_count_ is to deal with the padding problem
-    // max_count_ is depend on caller, eg: naive and splitN welford will have different
+    // max_count_ is depend on caller, eg: naive and splitN norm_reduce will have different
     // calculation of max_count_
     // -> use block_welford_calculate_max_count to compute
     template <typename XDistributedTensor_,
@@ -40,18 +41,24 @@ struct BlockWelford
             if(cur_count_ < max_count_)
             {
                 ++cur_count_;
-
                 sweep_tile_span(spans[I0], [&](auto dstr_idx_i0) {
                     constexpr auto in_dstr_idx  = make_tuple(dstr_idx_i0, dstr_idx_i1);
                     constexpr auto out_dstr_idx = make_tuple(dstr_idx_i0);
 
                     auto x = ck_tile::type_convert<ComputeDataType>(x_tensor[in_dstr_idx]);
-
-                    welford_update(mean_tensor(out_dstr_idx),
-                                   var_tensor(out_dstr_idx),
-                                   x,
-                                   cur_count_,
-                                   constant<kFastFDiv>{});
+                    if(kWelford)
+                    {
+                        welford_update(mean_tensor(out_dstr_idx),
+                                       var_tensor(out_dstr_idx),
+                                       x,
+                                       cur_count_,
+                                       constant<kFastFDiv>{});
+                    }
+                    else
+                    {
+                        mean_tensor(out_dstr_idx) += x;
+                        var_tensor(out_dstr_idx) += x * x;
+                    }
                 });
             }
         });
@@ -91,10 +98,11 @@ struct BlockWelford
 };
 
 template <typename Problem_, typename Policy_ = void>
-struct BlockWelfordSync
+struct BlockNormReduceSync
 {
     using Problem                   = remove_cvref_t<Problem_>;
     static constexpr bool kFastFDiv = Problem::kFastFDiv;
+    static constexpr bool kWelford  = Problem::kWelford;
 
     template <typename MeanDistributedTensor_, typename VarDistributedTensor_>
     CK_TILE_DEVICE void
@@ -152,36 +160,48 @@ struct BlockWelfordSync
                             (number<lid_over_rid_derivative << istage.value>{}.value);
 
                         // pull data from remote lane
-                        const auto v_remote_mean  = warp_shuffle(v_local_mean, src_lane);
-                        const auto v_remote_var   = warp_shuffle(v_local_var, src_lane);
-                        const auto v_remote_count = warp_shuffle(v_local_count, src_lane);
-
-                        // welford merge
-                        welford_merge(v_local_mean,
-                                      v_local_var,
-                                      v_local_count,
-                                      v_remote_mean,
-                                      v_remote_var,
-                                      v_remote_count,
-                                      constant<kFastFDiv>{});
+                        const auto v_remote_mean = warp_shuffle(v_local_mean, src_lane);
+                        const auto v_remote_var  = warp_shuffle(v_local_var, src_lane);
+                        if(kWelford)
+                        {
+                            const auto v_remote_count = warp_shuffle(v_local_count, src_lane);
+
+                            // norm_reduce merge
+                            welford_merge(v_local_mean,
+                                          v_local_var,
+                                          v_local_count,
+                                          v_remote_mean,
+                                          v_remote_var,
+                                          v_remote_count,
+                                          constant<kFastFDiv>{});
+                        }
+                        else
+                        {
+                            v_local_mean += v_remote_mean;
+                            v_local_var += v_remote_var;
+                        }
                     });
                 }
             });
 
             mean_tensor.get_thread_buffer()(i) = v_local_mean;
             var_tensor.get_thread_buffer()(i)  = v_local_var;
-
-            count = v_local_count;
+            if(kWelford)
+            {
+                count = v_local_count;
+            }
         });
     }
 };
 
 template <typename Problem_, typename Policy_ = void>
-struct BlockWelfordCrossWarpSync
+struct BlockNormReduceCrossWarpSync
 {
     using Problem                   = remove_cvref_t<Problem_>;
     using BlockShape                = typename Problem::BlockShape;
     static constexpr bool kFastFDiv = Problem::kFastFDiv;
+    static constexpr bool kWelford  = Problem::kWelford;
+    using smem_dtype                = std::conditional_t<kWelford, fp32x4_t, fp32x2_t>;
 
     template <typename MeanDistributedTensor_>
     CK_TILE_DEVICE static constexpr index_t GetReduceWarps()
@@ -252,7 +272,7 @@ struct BlockWelfordCrossWarpSync
         static_assert(thread_buf_size == VarDistributedTensor_::get_thread_buffer_size());
 
         // Note: we always pack everything into fp32x4
-        fp32x4_t* smem_ptr              = reinterpret_cast<fp32x4_t*>(smem);
+        smem_dtype* smem_ptr            = reinterpret_cast<smem_dtype*>(smem);
         const index_t lane_id           = get_lane_id();
         const index_t warp_id           = get_warp_id();
         constexpr auto num_reduce_warps = GetReduceWarps<MeanDistributedTensor_>();
@@ -267,11 +287,13 @@ struct BlockWelfordCrossWarpSync
         if(lane_id == 0)
         {
             static_for<0, thread_buf_size, 1>{}([&](auto i) {
-                fp32x4_t local_scratch_;
+                smem_dtype local_scratch_;
                 local_scratch_[0] = bit_cast<float>(mean_tensor.get_thread_buffer()[i]);
                 local_scratch_[1] = bit_cast<float>(var_tensor.get_thread_buffer()[i]);
-                local_scratch_[2] = bit_cast<float>(count);
-
+                if(kWelford)
+                {
+                    local_scratch_[2] = bit_cast<float>(count);
+                }
                 smem_ptr[smem_offset + i * num_warps] = local_scratch_;
             });
         }
@@ -280,7 +302,7 @@ struct BlockWelfordCrossWarpSync
         // load from smem. here we let everythread to do compute :)
         index_t local_warp_id = warp_id / num_reduce_warps;
         index_t local_smem_os = local_warp_id * num_reduce_warps;
-        fp32x4_t all_scratch[thread_buf_size * num_reduce_warps];
+        smem_dtype all_scratch[thread_buf_size * num_reduce_warps];
         static_for<0, thread_buf_size, 1>{}([&](auto i_0) {
             static_for<0, num_reduce_warps, 1>{}([&](auto i_1) {
                 all_scratch[i_0 * num_reduce_warps + i_1] =
@@ -293,32 +315,40 @@ struct BlockWelfordCrossWarpSync
 
         static_for<0, thread_buf_size, 1>{}([&](auto i_0) {
             // TODO: use descriptor for this
-            auto v_local       = all_scratch[i_0 * num_reduce_warps];
-            auto v_local_mean  = bit_cast<DataType>(v_local[0]);
-            auto v_local_var   = bit_cast<DataType>(v_local[1]);
-            auto v_local_count = bit_cast<int>(v_local[2]);
+            auto v_local      = all_scratch[i_0 * num_reduce_warps];
+            auto v_local_mean = bit_cast<DataType>(v_local[0]);
+            auto v_local_var  = bit_cast<DataType>(v_local[1]);
+            int v_local_count = kWelford ? bit_cast<int>(v_local[2]) : 0;
 
             // further reduce mean/var
             static_for<0, num_reduce_warps - 1, 1>{}([&](auto i_1_n1) {
                 constexpr auto i_1        = number<i_1_n1 + 1>{};
-                const fp32x4_t v_remote   = all_scratch[i_0 * num_reduce_warps + i_1];
+                const smem_dtype v_remote = all_scratch[i_0 * num_reduce_warps + i_1];
                 const auto v_remote_mean  = bit_cast<DataType>(v_remote[0]);
                 const auto v_remote_var   = bit_cast<DataType>(v_remote[1]);
-                const auto v_remote_count = bit_cast<int>(v_remote[2]);
-
-                welford_merge(v_local_mean,
-                              v_local_var,
-                              v_local_count,
-                              v_remote_mean,
-                              v_remote_var,
-                              v_remote_count,
-                              constant<kFastFDiv>{});
+                if(kWelford)
+                {
+                    const auto v_remote_count = bit_cast<int>(v_remote[2]);
+
+                    welford_merge(v_local_mean,
+                                  v_local_var,
+                                  v_local_count,
+                                  v_remote_mean,
+                                  v_remote_var,
+                                  v_remote_count,
+                                  constant<kFastFDiv>{});
+                }
+                else
+                {
+                    v_local_mean += v_remote_mean;
+                    v_local_var += v_remote_var;
+                }
             });
 
             mean_tensor.get_thread_buffer()(i_0) = v_local_mean;
             var_tensor.get_thread_buffer()(i_0)  = v_local_var;
-
-            count = v_local_count;
+            if(kWelford)
+                count = v_local_count;
         });
     }
 };

include/ck_tile/ops/welford/block/block_welford_problem.hpp → include/ck_tile/ops/norm_reduce/block/block_norm_reduce_problem.hpp

@@ -7,13 +7,18 @@
 
 namespace ck_tile {
 
-template <typename XDataType_, typename ComputeDataType_, typename BlockShape_, bool kFastFDiv_>
-struct BlockWelfordProblem
+template <typename XDataType_,
+          typename ComputeDataType_,
+          typename BlockShape_,
+          bool kFastFDiv_,
+          bool kWelford_>
+struct BlockNormReduceProblem
 {
     using XDataType                 = remove_cvref_t<XDataType_>;
     using ComputeDataType           = remove_cvref_t<ComputeDataType_>;
     using BlockShape                = remove_cvref_t<BlockShape_>;
     static constexpr bool kFastFDiv = kFastFDiv_;
+    static constexpr bool kWelford  = kWelford_;
 };
 
 } // namespace ck_tile