chromium/third_party/highway/src/hwy/timer.cc

// Copyright 2019 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// 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.

#include "hwy/timer.h"

#include <stdlib.h>

#include <chrono>  // NOLINT
#include <ratio>   // NOLINT

#include "hwy/base.h"
#include "hwy/robust_statistics.h"
#include "hwy/timer-inl.h"

#if HWY_ARCH_X86 && !HWY_COMPILER_MSVC
#include <cpuid.h>  // NOLINT
#endif

namespace hwy {
timer;

namespace platform {
namespace {

// Measures the actual current frequency of Ticks. We cannot rely on the nominal
// frequency encoded in x86 GetCpuString because it is misleading on M1 Rosetta,
// and not reported by AMD. CPUID 0x15 is also not yet widely supported. Also
// used on RISC-V and aarch64.
HWY_MAYBE_UNUSED double MeasureNominalClockRate() { … }

#if HWY_ARCH_X86

void Cpuid(const uint32_t level, const uint32_t count,
           uint32_t* HWY_RESTRICT abcd) { … }

bool HasRDTSCP() { … }

#endif  // HWY_ARCH_X86
}  // namespace

HWY_DLLEXPORT bool GetCpuString(char* cpu100) { … }

HWY_DLLEXPORT double Now() { … }

HWY_DLLEXPORT bool HaveTimerStop(char* cpu100) { … }

HWY_DLLEXPORT double InvariantTicksPerSecond() { … }

HWY_DLLEXPORT uint64_t TimerResolution() { … }

}  // namespace platform
}  // namespace hwy