wpleonardo commented on code in PR #1375: URL: https://github.com/apache/orc/pull/1375#discussion_r1107120791
########## c++/src/Dispatch.hh: ########## @@ -0,0 +1,109 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef ORC_DISPATCH_HH +#define ORC_DISPATCH_HH + +#include <utility> +#include <vector> + +#include "CpuInfoUtil.hh" + +namespace orc { + enum class DispatchLevel : int { + // These dispatch levels, corresponding to instruction set features, + // are sorted in increasing order of preference. + NONE = 0, + AVX512, + MAX + }; + + /* + A facility for dynamic dispatch according to available DispatchLevel. + + Typical use: + + static void my_function_default(...); + static void my_function_avx512(...); + + struct MyDynamicFunction { + using FunctionType = decltype(&my_function_default); + + static std::vector<std::pair<DispatchLevel, FunctionType>> implementations() { + return { + { DispatchLevel::NONE, my_function_default } + #if defined(ARROW_HAVE_RUNTIME_AVX512) + , { DispatchLevel::AVX512, my_function_avx512 } + #endif + }; + } + }; + + void my_function(...) { + static DynamicDispatch<MyDynamicFunction> dispatch; + return dispatch.func(...); + } + */ + template <typename DynamicFunction> + class DynamicDispatch { + protected: + using FunctionType = typename DynamicFunction::FunctionType; + using Implementation = std::pair<DispatchLevel, FunctionType>; + + public: + DynamicDispatch() { + Resolve(DynamicFunction::implementations()); + } + + FunctionType func = {}; + + protected: + // Use the Implementation with the highest DispatchLevel + void Resolve(const std::vector<Implementation>& implementations) { + Implementation cur{DispatchLevel::NONE, {}}; + + for (const auto& impl : implementations) { + if (impl.first >= cur.first && IsSupported(impl.first)) { + // Higher (or same) level than current + cur = impl; + } + } + + if (!cur.second) { + throw InvalidArgument("No appropriate implementation found"); + } + func = cur.second; + } + + private: + bool IsSupported(DispatchLevel level) const { + static const auto cpu_info = orc::CpuInfo::GetInstance(); Review Comment: Fixed ########## c++/src/Dispatch.hh: ########## @@ -0,0 +1,109 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef ORC_DISPATCH_HH +#define ORC_DISPATCH_HH + +#include <utility> +#include <vector> + +#include "CpuInfoUtil.hh" + +namespace orc { + enum class DispatchLevel : int { + // These dispatch levels, corresponding to instruction set features, + // are sorted in increasing order of preference. + NONE = 0, + AVX512, + MAX + }; + + /* + A facility for dynamic dispatch according to available DispatchLevel. + + Typical use: + + static void my_function_default(...); + static void my_function_avx512(...); + + struct MyDynamicFunction { + using FunctionType = decltype(&my_function_default); + + static std::vector<std::pair<DispatchLevel, FunctionType>> implementations() { + return { + { DispatchLevel::NONE, my_function_default } + #if defined(ARROW_HAVE_RUNTIME_AVX512) Review Comment: Fixed -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
