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Diffstat (limited to 'third_party/abseil_cpp/absl/base/internal/unscaledcycleclock.h')
| -rw-r--r-- | third_party/abseil_cpp/absl/base/internal/unscaledcycleclock.h | 124 |
1 files changed, 0 insertions, 124 deletions
diff --git a/third_party/abseil_cpp/absl/base/internal/unscaledcycleclock.h b/third_party/abseil_cpp/absl/base/internal/unscaledcycleclock.h deleted file mode 100644 index 82f2c87a95a9..000000000000 --- a/third_party/abseil_cpp/absl/base/internal/unscaledcycleclock.h +++ /dev/null @@ -1,124 +0,0 @@ -// Copyright 2017 The Abseil Authors. -// -// 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 -// -// https://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. -// -// UnscaledCycleClock -// An UnscaledCycleClock yields the value and frequency of a cycle counter -// that increments at a rate that is approximately constant. -// This class is for internal use only, you should consider using CycleClock -// instead. -// -// Notes: -// The cycle counter frequency is not necessarily the core clock frequency. -// That is, CycleCounter cycles are not necessarily "CPU cycles". -// -// An arbitrary offset may have been added to the counter at power on. -// -// On some platforms, the rate and offset of the counter may differ -// slightly when read from different CPUs of a multiprocessor. Usually, -// we try to ensure that the operating system adjusts values periodically -// so that values agree approximately. If you need stronger guarantees, -// consider using alternate interfaces. -// -// The CPU is not required to maintain the ordering of a cycle counter read -// with respect to surrounding instructions. - -#ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_ -#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_ - -#include <cstdint> - -#if defined(__APPLE__) -#include <TargetConditionals.h> -#endif - -#include "absl/base/port.h" - -// The following platforms have an implementation of a hardware counter. -#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \ - defined(__powerpc__) || defined(__ppc__) || \ - defined(_M_IX86) || defined(_M_X64) -#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1 -#else -#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0 -#endif - -// The following platforms often disable access to the hardware -// counter (through a sandbox) even if the underlying hardware has a -// usable counter. The CycleTimer interface also requires a *scaled* -// CycleClock that runs at atleast 1 MHz. We've found some Android -// ARM64 devices where this is not the case, so we disable it by -// default on Android ARM64. -#if defined(__native_client__) || \ - (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) || \ - (defined(__ANDROID__) && defined(__aarch64__)) -#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0 -#else -#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1 -#endif - -// UnscaledCycleClock is an optional internal feature. -// Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence. -// Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1 -#if !defined(ABSL_USE_UNSCALED_CYCLECLOCK) -#define ABSL_USE_UNSCALED_CYCLECLOCK \ - (ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \ - ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT) -#endif - -#if ABSL_USE_UNSCALED_CYCLECLOCK - -// This macro can be used to test if UnscaledCycleClock::Frequency() -// is NominalCPUFrequency() on a particular platform. -#if (defined(__i386__) || defined(__x86_64__) || \ - defined(_M_IX86) || defined(_M_X64)) -#define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY -#endif - -namespace absl { -ABSL_NAMESPACE_BEGIN -namespace time_internal { -class UnscaledCycleClockWrapperForGetCurrentTime; -} // namespace time_internal - -namespace base_internal { -class CycleClock; -class UnscaledCycleClockWrapperForInitializeFrequency; - -class UnscaledCycleClock { - private: - UnscaledCycleClock() = delete; - - // Return the value of a cycle counter that counts at a rate that is - // approximately constant. - static int64_t Now(); - - // Return the how much UnscaledCycleClock::Now() increases per second. - // This is not necessarily the core CPU clock frequency. - // It may be the nominal value report by the kernel, rather than a measured - // value. - static double Frequency(); - - // Allowed users - friend class base_internal::CycleClock; - friend class time_internal::UnscaledCycleClockWrapperForGetCurrentTime; - friend class base_internal::UnscaledCycleClockWrapperForInitializeFrequency; -}; - -} // namespace base_internal -ABSL_NAMESPACE_END -} // namespace absl - -#endif // ABSL_USE_UNSCALED_CYCLECLOCK - -#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_H_ |