coderex2522 commented on code in PR #1375: URL: https://github.com/apache/orc/pull/1375#discussion_r1105379569
########## c++/src/CpuInfoUtil.hh: ########## @@ -0,0 +1,110 @@ +/** + * 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_CPUINFOUTIL_HH +#define ORC_CPUINFOUTIL_HH + +#include <cstdint> +#include <memory> +#include <string> + +namespace orc { + + /// CpuInfo is an interface to query for cpu information at runtime. The caller can + /// ask for the sizes of the caches and what hardware features are supported. + /// On Linux, this information is pulled from a couple of sys files (/proc/cpuinfo and + /// /sys/devices) + class CpuInfo { + public: + ~CpuInfo(); + + /// x86 features + static constexpr int64_t SSSE3 = (1LL << 0); + static constexpr int64_t SSE4_1 = (1LL << 1); + static constexpr int64_t SSE4_2 = (1LL << 2); + static constexpr int64_t POPCNT = (1LL << 3); + static constexpr int64_t AVX = (1LL << 4); + static constexpr int64_t AVX2 = (1LL << 5); + static constexpr int64_t AVX512F = (1LL << 6); + static constexpr int64_t AVX512CD = (1LL << 7); + static constexpr int64_t AVX512VL = (1LL << 8); + static constexpr int64_t AVX512DQ = (1LL << 9); + static constexpr int64_t AVX512BW = (1LL << 10); + static constexpr int64_t AVX512 = AVX512F | AVX512CD | AVX512VL | AVX512DQ | AVX512BW; + static constexpr int64_t BMI1 = (1LL << 11); + static constexpr int64_t BMI2 = (1LL << 12); + + /// Arm features + static constexpr int64_t ASIMD = (1LL << 32); + + /// Cache enums for L1 (data), L2 and L3 + enum class CacheLevel { L1 = 0, L2, L3, Last = L3 }; + + /// CPU vendors + enum class Vendor { Unknown, Intel, AMD }; + + static const CpuInfo* GetInstance(); + + /// Returns all the flags for this cpu + int64_t hardwareFlags() const; + + /// Returns the number of cores (including hyper-threaded) on this machine. + int numCores() const; + + /// Returns the vendor of the cpu. + Vendor vendor() const; + + /// Returns the model name of the cpu (e.g. Intel i7-2600) + const std::string& modelName() const; + + /// Returns the size of the cache in KB at this cache level + int64_t CacheSize(CacheLevel level) const; + + /// \brief Returns whether or not the given feature is enabled. + /// + /// IsSupported() is true if IsDetected() is also true and the feature + /// wasn't disabled by the user (for example by setting the ORC_USER_SIMD_LEVEL + /// environment variable). + bool IsSupported(int64_t flags) const; + + /// Returns whether or not the given feature is available on the CPU. + bool IsDetected(int64_t flags) const; + + /// Determine if the CPU meets the minimum CPU requirements and if not, issue an error + /// and terminate. + void VerifyCpuRequirements() const; + + /// Toggle a hardware feature on and off. It is not valid to turn on a feature + /// that the underlying hardware cannot support. This is useful for testing. + // void EnableFeature(int64_t flag, bool enable); + + bool HasEfficientBmi2() const { + // BMI2 (pext, pdep) is only efficient on Intel X86 processors. + return vendor() == Vendor::Intel && IsSupported(BMI2); + } + + private: + CpuInfo(); + + struct Impl; + std::unique_ptr<Impl> impl_; Review Comment: If class CpuInfo is only a interface, I suggest that the impl_ variable should be removed from class CpuInfo. -- 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]
