/* * Copyright (c) Facebook, Inc. and its affiliates. * * Licensed 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. */ #pragma once #include <folly/Portability.h> #include <chrono> #include <cstdint> #if defined(_MSC_VER) extern "C" std::uint64_t __rdtsc(); #pragma intrinsic(__rdtsc) #endif namespace folly { inline std::uint64_t hardware_timestamp() { #if defined(_MSC_VER) return __rdtsc(); #elif defined(__GNUC__) && (defined(__i386__) || FOLLY_X64) return __builtin_ia32_rdtsc(); #else // use steady_clock::now() as an approximation for the timestamp counter on // non-x86 systems return std::chrono::steady_clock::now().time_since_epoch().count(); #endif } } // namespace folly