LLVM OpenMP* Runtime Library
kmp_stats_timing.cpp
1 
5 //===----------------------------------------------------------------------===//
6 //
7 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
8 // See https://llvm.org/LICENSE.txt for license information.
9 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include <stdlib.h>
14 #include <unistd.h>
15 
16 #include <iomanip>
17 #include <iostream>
18 #include <sstream>
19 
20 #include "kmp.h"
21 #include "kmp_stats_timing.h"
22 
23 using namespace std;
24 
25 #if KMP_HAVE_TICK_TIME
26 #if KMP_MIC
27 double tsc_tick_count::tick_time() {
28  // pretty bad assumption of 1GHz clock for MIC
29  return 1 / ((double)1000 * 1.e6);
30 }
31 #elif KMP_ARCH_X86 || KMP_ARCH_X86_64
32 #include <string.h>
33 // Extract the value from the CPUID information
34 double tsc_tick_count::tick_time() {
35  static double result = 0.0;
36 
37  if (result == 0.0) {
38  kmp_cpuid_t cpuinfo;
39  char brand[256];
40 
41  __kmp_x86_cpuid(0x80000000, 0, &cpuinfo);
42  memset(brand, 0, sizeof(brand));
43  int ids = cpuinfo.eax;
44 
45  for (unsigned int i = 2; i < (ids ^ 0x80000000) + 2; i++)
46  __kmp_x86_cpuid(i | 0x80000000, 0,
47  (kmp_cpuid_t *)(brand + (i - 2) * sizeof(kmp_cpuid_t)));
48 
49  char *start = &brand[0];
50  for (; *start == ' '; start++)
51  ;
52 
53  char *end = brand + KMP_STRLEN(brand) - 3;
54  uint64_t multiplier;
55 
56  if (*end == 'M')
57  multiplier = 1000LL * 1000LL;
58  else if (*end == 'G')
59  multiplier = 1000LL * 1000LL * 1000LL;
60  else if (*end == 'T')
61  multiplier = 1000LL * 1000LL * 1000LL * 1000LL;
62  else {
63  cout << "Error determining multiplier '" << *end << "'\n";
64  exit(-1);
65  }
66  *end = 0;
67  while (*end != ' ')
68  end--;
69  end++;
70 
71  double freq = strtod(end, &start);
72  if (freq == 0.0) {
73  cout << "Error calculating frequency " << end << "\n";
74  exit(-1);
75  }
76 
77  result = ((double)1.0) / (freq * multiplier);
78  }
79  return result;
80 }
81 #endif
82 #endif
83 
84 static bool useSI = true;
85 
86 // Return a formatted string after normalising the value into
87 // engineering style and using a suitable unit prefix (e.g. ms, us, ns).
88 std::string formatSI(double interval, int width, char unit) {
89  std::stringstream os;
90 
91  if (useSI) {
92  // Preserve accuracy for small numbers, since we only multiply and the
93  // positive powers of ten are precisely representable.
94  static struct {
95  double scale;
96  char prefix;
97  } ranges[] = {{1.e21, 'y'}, {1.e18, 'z'}, {1.e15, 'a'}, {1.e12, 'f'},
98  {1.e9, 'p'}, {1.e6, 'n'}, {1.e3, 'u'}, {1.0, 'm'},
99  {1.e-3, ' '}, {1.e-6, 'k'}, {1.e-9, 'M'}, {1.e-12, 'G'},
100  {1.e-15, 'T'}, {1.e-18, 'P'}, {1.e-21, 'E'}, {1.e-24, 'Z'},
101  {1.e-27, 'Y'}};
102 
103  if (interval == 0.0) {
104  os << std::setw(width - 3) << std::right << "0.00" << std::setw(3)
105  << unit;
106  return os.str();
107  }
108 
109  bool negative = false;
110  if (interval < 0.0) {
111  negative = true;
112  interval = -interval;
113  }
114 
115  for (int i = 0; i < (int)(sizeof(ranges) / sizeof(ranges[0])); i++) {
116  if (interval * ranges[i].scale < 1.e0) {
117  interval = interval * 1000.e0 * ranges[i].scale;
118  os << std::fixed << std::setprecision(2) << std::setw(width - 3)
119  << std::right << (negative ? -interval : interval) << std::setw(2)
120  << ranges[i].prefix << std::setw(1) << unit;
121 
122  return os.str();
123  }
124  }
125  }
126  os << std::setprecision(2) << std::fixed << std::right << std::setw(width - 3)
127  << interval << std::setw(3) << unit;
128 
129  return os.str();
130 }