unscaledcycleclock_config.h (2535B)
1 // Copyright 2022 The Abseil Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_ 16 #define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_ 17 18 #if defined(__APPLE__) 19 #include <TargetConditionals.h> 20 #endif 21 22 // The following platforms have an implementation of a hardware counter. 23 #if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \ 24 defined(__powerpc__) || defined(__ppc__) || defined(_M_IX86) || \ 25 (defined(_M_X64) && !defined(_M_ARM64EC)) 26 #define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1 27 #else 28 #define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0 29 #endif 30 31 // The following platforms often disable access to the hardware 32 // counter (through a sandbox) even if the underlying hardware has a 33 // usable counter. The CycleTimer interface also requires a *scaled* 34 // CycleClock that runs at atleast 1 MHz. We've found some Android 35 // ARM64 devices where this is not the case, so we disable it by 36 // default on Android ARM64. 37 #if defined(__native_client__) || (defined(__APPLE__)) || \ 38 (defined(__ANDROID__) && defined(__aarch64__)) 39 #define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0 40 #else 41 #define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1 42 #endif 43 44 // UnscaledCycleClock is an optional internal feature. 45 // Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence. 46 // Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1 47 #if !defined(ABSL_USE_UNSCALED_CYCLECLOCK) 48 #define ABSL_USE_UNSCALED_CYCLECLOCK \ 49 (ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \ 50 ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT) 51 #endif 52 53 #if ABSL_USE_UNSCALED_CYCLECLOCK 54 // This macro can be used to test if UnscaledCycleClock::Frequency() 55 // is NominalCPUFrequency() on a particular platform. 56 #if (defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || \ 57 defined(_M_X64)) 58 #define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY 59 #endif 60 #endif 61 62 #endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_