summaryrefslogtreecommitdiff
path: root/absl/base/internal/unscaledcycleclock.cc
blob: 05e0e7ba5ee95d67d8321c4da46462ca751fa57b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
// 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.

#include "absl/base/internal/unscaledcycleclock.h"

#if ABSL_USE_UNSCALED_CYCLECLOCK

#if defined(_WIN32)
#include <intrin.h>
#endif

#if defined(__powerpc__) || defined(__ppc__)
#ifdef __GLIBC__
#include <sys/platform/ppc.h>
#elif defined(__FreeBSD__)
// clang-format off
// This order does actually matter =(.
#include <sys/types.h>
#include <sys/sysctl.h>
// clang-format on

#include "absl/base/call_once.h"
#endif
#endif

#include "absl/base/internal/sysinfo.h"

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {

#if defined(__i386__)

int64_t UnscaledCycleClock::Now() {
  int64_t ret;
  __asm__ volatile("rdtsc" : "=A"(ret));
  return ret;
}

double UnscaledCycleClock::Frequency() {
  return base_internal::NominalCPUFrequency();
}

#elif defined(__x86_64__)

double UnscaledCycleClock::Frequency() {
  return base_internal::NominalCPUFrequency();
}

#elif defined(__powerpc__) || defined(__ppc__)

int64_t UnscaledCycleClock::Now() {
#ifdef __GLIBC__
  return __ppc_get_timebase();
#else
#ifdef __powerpc64__
  int64_t tbr;
  asm volatile("mfspr %0, 268" : "=r"(tbr));
  return tbr;
#else
  int32_t tbu, tbl, tmp;
  asm volatile(
      "mftbu %[hi32]\n"
      "mftb %[lo32]\n"
      "mftbu %[tmp]\n"
      "cmpw %[tmp],%[hi32]\n"
      "bne $-16\n"  // Retry on failure.
      : [hi32] "=r"(tbu), [lo32] "=r"(tbl), [tmp] "=r"(tmp));
  return (static_cast<int64_t>(tbu) << 32) | tbl;
#endif
#endif
}

double UnscaledCycleClock::Frequency() {
#ifdef __GLIBC__
  return __ppc_get_timebase_freq();
#elif defined(_AIX)
  // This is the same constant value as returned by
  // __ppc_get_timebase_freq().
  return static_cast<double>(512000000);
#elif defined(__FreeBSD__)
  static once_flag init_timebase_frequency_once;
  static double timebase_frequency = 0.0;
  base_internal::LowLevelCallOnce(&init_timebase_frequency_once, [&]() {
    size_t length = sizeof(timebase_frequency);
    sysctlbyname("kern.timecounter.tc.timebase.frequency", &timebase_frequency,
                 &length, nullptr, 0);
  });
  return timebase_frequency;
#else
#error Must implement UnscaledCycleClock::Frequency()
#endif
}

#elif defined(__aarch64__)

// System timer of ARMv8 runs at a different frequency than the CPU's.
// The frequency is fixed, typically in the range 1-50MHz.  It can be
// read at CNTFRQ special register.  We assume the OS has set up
// the virtual timer properly.
int64_t UnscaledCycleClock::Now() {
  int64_t virtual_timer_value;
  asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
  return virtual_timer_value;
}

double UnscaledCycleClock::Frequency() {
  uint64_t aarch64_timer_frequency;
  asm volatile("mrs %0, cntfrq_el0" : "=r"(aarch64_timer_frequency));
  return aarch64_timer_frequency;
}

#elif defined(__riscv)

int64_t UnscaledCycleClock::Now() {
  int64_t virtual_timer_value;
  asm volatile("rdcycle %0" : "=r"(virtual_timer_value));
  return virtual_timer_value;
}

double UnscaledCycleClock::Frequency() {
  return base_internal::NominalCPUFrequency();
}

#elif defined(_M_IX86) || defined(_M_X64)

#pragma intrinsic(__rdtsc)

int64_t UnscaledCycleClock::Now() { return __rdtsc(); }

double UnscaledCycleClock::Frequency() {
  return base_internal::NominalCPUFrequency();
}

#endif

}  // namespace base_internal
ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_USE_UNSCALED_CYCLECLOCK