topk_softmax (#1592)

* topk_softmax

* remove some file

* fix atomix linear_offset

* address various comment, and change sfc get_index api to static(tuple)

include/ck_tile/ops/topk/block/block_topk_stream_2d.hpp

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
+
+#pragma once
+
+#include "ck_tile/core.hpp"
+
+namespace ck_tile {
+
+/*
+simple 2d topk implementation, along row (dim=1)
+requirement:
+    1). each row is within a warp
+*/
+template <typename Problem_, typename Policy_ = void>
+struct BlockTopkStream2D
+{
+    using Problem = remove_cvref_t<Problem_>;
+    using Policy  = remove_cvref_t<Policy_>;
+
+    using DataType  = typename Problem::DataType;
+    using IndexType = typename Problem::IndexType;
+
+    // TODO: if DataType is subdword, need pack into single dword to use argmax
+    struct ArgmaxPacket
+    {
+        DataType arg;
+        index_t value;
+    };
+
+    template <typename DistributedTensor, typename OutWindow, typename IdxWindow, index_t dim = 1>
+    CK_TILE_DEVICE void operator()(const DistributedTensor& x,
+                                   const OutWindow& out_window,
+                                   const IdxWindow& idx_window,
+                                   index_t k,
+                                   number<dim> = {})
+    {
+        OutWindow out_window_tmp = out_window;
+        IdxWindow idx_window_tmp = idx_window;
+        static_assert(
+            std::is_same_v<typename DistributedTensor::DataType, typename OutWindow::DataType> &&
+            std::is_same_v<typename DistributedTensor::DataType, DataType>);
+        static_assert(std::is_same_v<typename IdxWindow::DataType, IndexType>);
+
+        DistributedTensor x_tmp = x;
+        constexpr auto dst_dist = typename IdxWindow::TileDstr{};
+
+        // argmax for topk
+        const auto f_argmax = [](ArgmaxPacket e0, ArgmaxPacket e1) {
+            return e0.arg > e1.arg ? e0 : e1;
+        };
+
+        for(index_t i_k = 0; i_k < k; i_k++)
+        {
+            constexpr auto span_2d = DistributedTensor::get_distributed_spans();
+            auto packet            = [&]() {
+                auto tmp = make_static_distributed_tensor<ArgmaxPacket>(x.get_tile_distribution());
+
+                sweep_tile_span(span_2d[number<0>{}], [&](auto idx0) {
+                    sweep_tile_span(span_2d[number<1>{}], [&](auto idx1) {
+                        const auto tile_idx = get_x_indices_from_distributed_indices(
+                            tmp.get_tile_distribution(), make_tuple(idx0, idx1));
+                        constexpr auto i_j_idx = make_tuple(idx0, idx1);
+                        ArgmaxPacket t;
+                        t.arg        = x_tmp(i_j_idx); // !!! we reference x here
+                        t.value      = tile_idx.at(number<1>{});
+                        tmp(i_j_idx) = t;
+                    });
+                });
+                return tmp;
+            }();
+
+            auto argmax_init = ArgmaxPacket{-numeric<DataType>::infinity(), 0};
+            auto r = block_tile_reduce<ArgmaxPacket>(packet, sequence<1>{}, f_argmax, argmax_init);
+            block_tile_reduce_xor_sync(r, f_argmax);
+
+            auto o = make_static_distributed_tensor<DataType>(dst_dist);
+            auto i = make_static_distributed_tensor<IndexType>(dst_dist);
+            sweep_tile_span(span_2d[number<0>{}], [&](auto idx0) {
+                sweep_tile_span(span_2d[number<1>{}], [&](auto idx1) {
+                    constexpr auto i_j_idx = make_tuple(idx0, idx1);
+                    ArgmaxPacket tmp       = r(i_j_idx);
+                    o(i_j_idx)             = tmp.arg;
+                    i(i_j_idx)             = tmp.value;
+                });
+            });
+
+            // update value
+            sweep_tile_span(span_2d[number<0>{}], [&](auto idx0) {
+                sweep_tile_span(span_2d[number<1>{}], [&](auto idx1) {
+                    const auto tile_idx = get_x_indices_from_distributed_indices(
+                        x.get_tile_distribution(), make_tuple(idx0, idx1));
+                    auto col_id = tile_idx.at(number<1>{});
+
+                    constexpr auto i_j_idx = make_tuple(idx0, idx1);
+
+                    x_tmp(i_j_idx) = (col_id == r(i_j_idx).value) ? -numeric<DataType>::infinity()
+                                                                  : x_tmp(i_j_idx);
+                });
+            });
+
+            if(threadIdx.x % Problem::ColLanes == 0)
+            {
+                store_tile(out_window_tmp, o);
+                store_tile(idx_window_tmp, i);
+            }
+            move_tile_window(out_window_tmp, {number<0>{}, number<1>{}});
+            move_tile_window(idx_window_tmp, {number<0>{}, number<1>{}});
+        }
+    }
+};
+
+} // namespace ck_tile

include/ck_tile/ops/topk/block/block_topk_stream_2d_problem.hpp

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
+
+#pragma once
+
+#include "ck_tile/core.hpp"
+
+namespace ck_tile {
+
+/*
+simple 2d topk implementation, along row (dim=1)
+requirement:
+    1). each row is within a warp
+*/
+template <typename DataType_, typename IndexType_, index_t ColLanes_>
+struct BlockTopkStream2DProblem
+{
+    using DataType                    = remove_cvref_t<DataType_>;
+    using IndexType                   = remove_cvref_t<IndexType_>;
+    static constexpr index_t ColLanes = ColLanes_;
+};
+} // namespace ck_tile