Abseil Common Libraries (C++) (grcp 依赖)
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101 lines
2.5 KiB
101 lines
2.5 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#include "absl/base/internal/unscaledcycleclock.h" |
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#if ABSL_USE_UNSCALED_CYCLECLOCK |
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#if defined(_WIN32) |
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#include <intrin.h> |
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#endif |
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#if defined(__powerpc__) || defined(__ppc__) |
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#include <sys/platform/ppc.h> |
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#endif |
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#include "absl/base/internal/sysinfo.h" |
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namespace absl { |
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namespace base_internal { |
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#if defined(__i386__) |
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int64_t UnscaledCycleClock::Now() { |
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int64_t ret; |
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__asm__ volatile("rdtsc" : "=A"(ret)); |
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return ret; |
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} |
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double UnscaledCycleClock::Frequency() { |
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return base_internal::NominalCPUFrequency(); |
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} |
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#elif defined(__x86_64__) |
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int64_t UnscaledCycleClock::Now() { |
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uint64_t low, high; |
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__asm__ volatile("rdtsc" : "=a"(low), "=d"(high)); |
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return (high << 32) | low; |
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} |
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double UnscaledCycleClock::Frequency() { |
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return base_internal::NominalCPUFrequency(); |
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} |
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#elif defined(__powerpc__) || defined(__ppc__) |
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int64_t UnscaledCycleClock::Now() { |
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return __ppc_get_timebase(); |
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} |
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double UnscaledCycleClock::Frequency() { |
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return __ppc_get_timebase_freq(); |
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} |
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#elif defined(__aarch64__) |
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// System timer of ARMv8 runs at a different frequency than the CPU's. |
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// The frequency is fixed, typically in the range 1-50MHz. It can be |
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// read at CNTFRQ special register. We assume the OS has set up |
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// the virtual timer properly. |
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int64_t UnscaledCycleClock::Now() { |
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int64_t virtual_timer_value; |
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asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value)); |
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return virtual_timer_value; |
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} |
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double UnscaledCycleClock::Frequency() { |
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uint64_t aarch64_timer_frequency; |
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asm volatile("mrs %0, cntfrq_el0" : "=r"(aarch64_timer_frequency)); |
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return aarch64_timer_frequency; |
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} |
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#elif defined(_M_IX86) || defined(_M_X64) |
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#pragma intrinsic(__rdtsc) |
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int64_t UnscaledCycleClock::Now() { |
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return __rdtsc(); |
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} |
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double UnscaledCycleClock::Frequency() { |
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return base_internal::NominalCPUFrequency(); |
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} |
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#endif |
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} // namespace base_internal |
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} // namespace absl |
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#endif // ABSL_USE_UNSCALED_CYCLECLOCK
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