1 | package Benchmark; |
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2 | |
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3 | =head1 NAME |
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4 | |
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5 | Benchmark - benchmark running times of Perl code |
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6 | |
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7 | =head1 SYNOPSIS |
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8 | |
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9 | use Benchmark qw(:all) ; |
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10 | |
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11 | timethis ($count, "code"); |
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12 | |
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13 | # Use Perl code in strings... |
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14 | timethese($count, { |
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15 | 'Name1' => '...code1...', |
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16 | 'Name2' => '...code2...', |
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17 | }); |
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18 | |
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19 | # ... or use subroutine references. |
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20 | timethese($count, { |
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21 | 'Name1' => sub { ...code1... }, |
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22 | 'Name2' => sub { ...code2... }, |
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23 | }); |
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24 | |
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25 | # cmpthese can be used both ways as well |
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26 | cmpthese($count, { |
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27 | 'Name1' => '...code1...', |
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28 | 'Name2' => '...code2...', |
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29 | }); |
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30 | |
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31 | cmpthese($count, { |
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32 | 'Name1' => sub { ...code1... }, |
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33 | 'Name2' => sub { ...code2... }, |
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34 | }); |
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35 | |
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36 | # ...or in two stages |
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37 | $results = timethese($count, |
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38 | { |
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39 | 'Name1' => sub { ...code1... }, |
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40 | 'Name2' => sub { ...code2... }, |
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41 | }, |
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42 | 'none' |
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43 | ); |
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44 | cmpthese( $results ) ; |
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45 | |
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46 | $t = timeit($count, '...other code...') |
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47 | print "$count loops of other code took:",timestr($t),"\n"; |
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48 | |
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49 | $t = countit($time, '...other code...') |
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50 | $count = $t->iters ; |
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51 | print "$count loops of other code took:",timestr($t),"\n"; |
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52 | |
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53 | =head1 DESCRIPTION |
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54 | |
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55 | The Benchmark module encapsulates a number of routines to help you |
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56 | figure out how long it takes to execute some code. |
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57 | |
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58 | timethis - run a chunk of code several times |
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59 | |
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60 | timethese - run several chunks of code several times |
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61 | |
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62 | cmpthese - print results of timethese as a comparison chart |
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63 | |
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64 | timeit - run a chunk of code and see how long it goes |
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65 | |
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66 | countit - see how many times a chunk of code runs in a given time |
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67 | |
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68 | |
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69 | =head2 Methods |
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70 | |
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71 | =over 10 |
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72 | |
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73 | =item new |
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74 | |
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75 | Returns the current time. Example: |
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76 | |
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77 | use Benchmark; |
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78 | $t0 = new Benchmark; |
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79 | # ... your code here ... |
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80 | $t1 = new Benchmark; |
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81 | $td = timediff($t1, $t0); |
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82 | print "the code took:",timestr($td),"\n"; |
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83 | |
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84 | =item debug |
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85 | |
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86 | Enables or disable debugging by setting the C<$Benchmark::Debug> flag: |
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87 | |
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88 | debug Benchmark 1; |
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89 | $t = timeit(10, ' 5 ** $Global '); |
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90 | debug Benchmark 0; |
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91 | |
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92 | =item iters |
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93 | |
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94 | Returns the number of iterations. |
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95 | |
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96 | =back |
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97 | |
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98 | =head2 Standard Exports |
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99 | |
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100 | The following routines will be exported into your namespace |
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101 | if you use the Benchmark module: |
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102 | |
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103 | =over 10 |
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104 | |
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105 | =item timeit(COUNT, CODE) |
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106 | |
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107 | Arguments: COUNT is the number of times to run the loop, and CODE is |
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108 | the code to run. CODE may be either a code reference or a string to |
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109 | be eval'd; either way it will be run in the caller's package. |
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110 | |
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111 | Returns: a Benchmark object. |
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112 | |
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113 | =item timethis ( COUNT, CODE, [ TITLE, [ STYLE ]] ) |
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114 | |
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115 | Time COUNT iterations of CODE. CODE may be a string to eval or a |
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116 | code reference; either way the CODE will run in the caller's package. |
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117 | Results will be printed to STDOUT as TITLE followed by the times. |
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118 | TITLE defaults to "timethis COUNT" if none is provided. STYLE |
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119 | determines the format of the output, as described for timestr() below. |
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120 | |
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121 | The COUNT can be zero or negative: this means the I<minimum number of |
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122 | CPU seconds> to run. A zero signifies the default of 3 seconds. For |
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123 | example to run at least for 10 seconds: |
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124 | |
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125 | timethis(-10, $code) |
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126 | |
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127 | or to run two pieces of code tests for at least 3 seconds: |
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128 | |
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129 | timethese(0, { test1 => '...', test2 => '...'}) |
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130 | |
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131 | CPU seconds is, in UNIX terms, the user time plus the system time of |
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132 | the process itself, as opposed to the real (wallclock) time and the |
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133 | time spent by the child processes. Less than 0.1 seconds is not |
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134 | accepted (-0.01 as the count, for example, will cause a fatal runtime |
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135 | exception). |
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136 | |
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137 | Note that the CPU seconds is the B<minimum> time: CPU scheduling and |
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138 | other operating system factors may complicate the attempt so that a |
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139 | little bit more time is spent. The benchmark output will, however, |
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140 | also tell the number of C<$code> runs/second, which should be a more |
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141 | interesting number than the actually spent seconds. |
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142 | |
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143 | Returns a Benchmark object. |
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144 | |
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145 | =item timethese ( COUNT, CODEHASHREF, [ STYLE ] ) |
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146 | |
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147 | The CODEHASHREF is a reference to a hash containing names as keys |
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148 | and either a string to eval or a code reference for each value. |
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149 | For each (KEY, VALUE) pair in the CODEHASHREF, this routine will |
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150 | call |
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151 | |
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152 | timethis(COUNT, VALUE, KEY, STYLE) |
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153 | |
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154 | The routines are called in string comparison order of KEY. |
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155 | |
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156 | The COUNT can be zero or negative, see timethis(). |
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157 | |
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158 | Returns a hash of Benchmark objects, keyed by name. |
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159 | |
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160 | =item timediff ( T1, T2 ) |
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161 | |
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162 | Returns the difference between two Benchmark times as a Benchmark |
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163 | object suitable for passing to timestr(). |
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164 | |
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165 | =item timestr ( TIMEDIFF, [ STYLE, [ FORMAT ] ] ) |
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166 | |
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167 | Returns a string that formats the times in the TIMEDIFF object in |
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168 | the requested STYLE. TIMEDIFF is expected to be a Benchmark object |
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169 | similar to that returned by timediff(). |
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170 | |
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171 | STYLE can be any of 'all', 'none', 'noc', 'nop' or 'auto'. 'all' shows |
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172 | each of the 5 times available ('wallclock' time, user time, system time, |
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173 | user time of children, and system time of children). 'noc' shows all |
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174 | except the two children times. 'nop' shows only wallclock and the |
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175 | two children times. 'auto' (the default) will act as 'all' unless |
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176 | the children times are both zero, in which case it acts as 'noc'. |
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177 | 'none' prevents output. |
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178 | |
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179 | FORMAT is the L<printf(3)>-style format specifier (without the |
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180 | leading '%') to use to print the times. It defaults to '5.2f'. |
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181 | |
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182 | =back |
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183 | |
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184 | =head2 Optional Exports |
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185 | |
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186 | The following routines will be exported into your namespace |
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187 | if you specifically ask that they be imported: |
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188 | |
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189 | =over 10 |
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190 | |
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191 | =item clearcache ( COUNT ) |
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192 | |
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193 | Clear the cached time for COUNT rounds of the null loop. |
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194 | |
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195 | =item clearallcache ( ) |
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196 | |
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197 | Clear all cached times. |
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198 | |
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199 | =item cmpthese ( COUT, CODEHASHREF, [ STYLE ] ) |
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200 | |
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201 | =item cmpthese ( RESULTSHASHREF, [ STYLE ] ) |
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202 | |
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203 | Optionally calls timethese(), then outputs comparison chart. This: |
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204 | |
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205 | cmpthese( -1, { a => "++\$i", b => "\$i *= 2" } ) ; |
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206 | |
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207 | outputs a chart like: |
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208 | |
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209 | Rate b a |
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210 | b 2831802/s -- -61% |
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211 | a 7208959/s 155% -- |
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212 | |
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213 | This chart is sorted from slowest to fastest, and shows the percent speed |
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214 | difference between each pair of tests. |
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215 | |
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216 | c<cmpthese> can also be passed the data structure that timethese() returns: |
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217 | |
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218 | $results = timethese( -1, { a => "++\$i", b => "\$i *= 2" } ) ; |
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219 | cmpthese( $results ); |
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220 | |
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221 | in case you want to see both sets of results. |
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222 | |
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223 | Returns a reference to an ARRAY of rows, each row is an ARRAY of cells from the |
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224 | above chart, including labels. This: |
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225 | |
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226 | my $rows = cmpthese( -1, { a => '++$i', b => '$i *= 2' }, "none" ); |
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227 | |
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228 | returns a data structure like: |
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229 | |
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230 | [ |
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231 | [ '', 'Rate', 'b', 'a' ], |
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232 | [ 'b', '2885232/s', '--', '-59%' ], |
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233 | [ 'a', '7099126/s', '146%', '--' ], |
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234 | ] |
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235 | |
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236 | B<NOTE>: This result value differs from previous versions, which returned |
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237 | the C<timethese()> result structure. If you want that, just use the two |
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238 | statement C<timethese>...C<cmpthese> idiom shown above. |
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239 | |
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240 | Incidently, note the variance in the result values between the two examples; |
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241 | this is typical of benchmarking. If this were a real benchmark, you would |
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242 | probably want to run a lot more iterations. |
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243 | |
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244 | =item countit(TIME, CODE) |
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245 | |
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246 | Arguments: TIME is the minimum length of time to run CODE for, and CODE is |
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247 | the code to run. CODE may be either a code reference or a string to |
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248 | be eval'd; either way it will be run in the caller's package. |
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249 | |
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250 | TIME is I<not> negative. countit() will run the loop many times to |
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251 | calculate the speed of CODE before running it for TIME. The actual |
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252 | time run for will usually be greater than TIME due to system clock |
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253 | resolution, so it's best to look at the number of iterations divided |
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254 | by the times that you are concerned with, not just the iterations. |
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255 | |
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256 | Returns: a Benchmark object. |
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257 | |
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258 | =item disablecache ( ) |
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259 | |
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260 | Disable caching of timings for the null loop. This will force Benchmark |
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261 | to recalculate these timings for each new piece of code timed. |
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262 | |
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263 | =item enablecache ( ) |
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264 | |
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265 | Enable caching of timings for the null loop. The time taken for COUNT |
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266 | rounds of the null loop will be calculated only once for each |
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267 | different COUNT used. |
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268 | |
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269 | =item timesum ( T1, T2 ) |
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270 | |
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271 | Returns the sum of two Benchmark times as a Benchmark object suitable |
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272 | for passing to timestr(). |
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273 | |
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274 | =back |
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275 | |
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276 | =head1 NOTES |
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277 | |
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278 | The data is stored as a list of values from the time and times |
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279 | functions: |
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280 | |
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281 | ($real, $user, $system, $children_user, $children_system, $iters) |
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282 | |
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283 | in seconds for the whole loop (not divided by the number of rounds). |
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284 | |
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285 | The timing is done using time(3) and times(3). |
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286 | |
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287 | Code is executed in the caller's package. |
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288 | |
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289 | The time of the null loop (a loop with the same |
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290 | number of rounds but empty loop body) is subtracted |
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291 | from the time of the real loop. |
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292 | |
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293 | The null loop times can be cached, the key being the |
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294 | number of rounds. The caching can be controlled using |
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295 | calls like these: |
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296 | |
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297 | clearcache($key); |
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298 | clearallcache(); |
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299 | |
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300 | disablecache(); |
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301 | enablecache(); |
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302 | |
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303 | Caching is off by default, as it can (usually slightly) decrease |
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304 | accuracy and does not usually noticably affect runtimes. |
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305 | |
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306 | =head1 EXAMPLES |
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307 | |
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308 | For example, |
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309 | |
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310 | use Benchmark qw( cmpthese ) ; |
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311 | $x = 3; |
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312 | cmpthese( -5, { |
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313 | a => sub{$x*$x}, |
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314 | b => sub{$x**2}, |
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315 | } ); |
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316 | |
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317 | outputs something like this: |
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318 | |
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319 | Benchmark: running a, b, each for at least 5 CPU seconds... |
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320 | Rate b a |
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321 | b 1559428/s -- -62% |
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322 | a 4152037/s 166% -- |
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323 | |
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324 | |
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325 | while |
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326 | |
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327 | use Benchmark qw( timethese cmpthese ) ; |
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328 | $x = 3; |
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329 | $r = timethese( -5, { |
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330 | a => sub{$x*$x}, |
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331 | b => sub{$x**2}, |
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332 | } ); |
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333 | cmpthese $r; |
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334 | |
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335 | outputs something like this: |
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336 | |
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337 | Benchmark: running a, b, each for at least 5 CPU seconds... |
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338 | a: 10 wallclock secs ( 5.14 usr + 0.13 sys = 5.27 CPU) @ 3835055.60/s (n=20210743) |
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339 | b: 5 wallclock secs ( 5.41 usr + 0.00 sys = 5.41 CPU) @ 1574944.92/s (n=8520452) |
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340 | Rate b a |
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341 | b 1574945/s -- -59% |
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342 | a 3835056/s 144% -- |
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343 | |
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344 | |
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345 | =head1 INHERITANCE |
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346 | |
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347 | Benchmark inherits from no other class, except of course |
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348 | for Exporter. |
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349 | |
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350 | =head1 CAVEATS |
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351 | |
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352 | Comparing eval'd strings with code references will give you |
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353 | inaccurate results: a code reference will show a slightly slower |
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354 | execution time than the equivalent eval'd string. |
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355 | |
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356 | The real time timing is done using time(2) and |
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357 | the granularity is therefore only one second. |
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358 | |
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359 | Short tests may produce negative figures because perl |
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360 | can appear to take longer to execute the empty loop |
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361 | than a short test; try: |
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362 | |
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363 | timethis(100,'1'); |
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364 | |
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365 | The system time of the null loop might be slightly |
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366 | more than the system time of the loop with the actual |
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367 | code and therefore the difference might end up being E<lt> 0. |
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368 | |
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369 | =head1 SEE ALSO |
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370 | |
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371 | L<Devel::DProf> - a Perl code profiler |
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372 | |
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373 | =head1 AUTHORS |
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374 | |
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375 | Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>> |
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376 | |
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377 | =head1 MODIFICATION HISTORY |
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378 | |
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379 | September 8th, 1994; by Tim Bunce. |
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380 | |
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381 | March 28th, 1997; by Hugo van der Sanden: added support for code |
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382 | references and the already documented 'debug' method; revamped |
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383 | documentation. |
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384 | |
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385 | April 04-07th, 1997: by Jarkko Hietaniemi, added the run-for-some-time |
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386 | functionality. |
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387 | |
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388 | September, 1999; by Barrie Slaymaker: math fixes and accuracy and |
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389 | efficiency tweaks. Added cmpthese(). A result is now returned from |
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390 | timethese(). Exposed countit() (was runfor()). |
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391 | |
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392 | December, 2001; by Nicholas Clark: make timestr() recognise the style 'none' |
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393 | and return an empty string. If cmpthese is calling timethese, make it pass the |
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394 | style in. (so that 'none' will suppress output). Make sub new dump its |
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395 | debugging output to STDERR, to be consistent with everything else. |
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396 | All bugs found while writing a regression test. |
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397 | |
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398 | =cut |
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399 | |
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400 | # evaluate something in a clean lexical environment |
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401 | sub _doeval { eval shift } |
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402 | |
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403 | # |
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404 | # put any lexicals at file scope AFTER here |
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405 | # |
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406 | |
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407 | use Carp; |
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408 | use Exporter; |
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409 | @ISA=(Exporter); |
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410 | @EXPORT=qw(timeit timethis timethese timediff timestr); |
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411 | @EXPORT_OK=qw(timesum cmpthese countit |
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412 | clearcache clearallcache disablecache enablecache); |
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413 | %EXPORT_TAGS=( all => [ @EXPORT, @EXPORT_OK ] ) ; |
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414 | |
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415 | $VERSION = 1.04; |
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416 | |
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417 | &init; |
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418 | |
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419 | sub init { |
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420 | $debug = 0; |
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421 | $min_count = 4; |
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422 | $min_cpu = 0.4; |
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423 | $defaultfmt = '5.2f'; |
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424 | $defaultstyle = 'auto'; |
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425 | # The cache can cause a slight loss of sys time accuracy. If a |
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426 | # user does many tests (>10) with *very* large counts (>10000) |
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427 | # or works on a very slow machine the cache may be useful. |
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428 | &disablecache; |
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429 | &clearallcache; |
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430 | } |
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431 | |
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432 | sub debug { $debug = ($_[1] != 0); } |
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433 | |
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434 | # The cache needs two branches: 's' for strings and 'c' for code. The |
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435 | # emtpy loop is different in these two cases. |
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436 | sub clearcache { delete $cache{"$_[0]c"}; delete $cache{"$_[0]s"}; } |
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437 | sub clearallcache { %cache = (); } |
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438 | sub enablecache { $cache = 1; } |
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439 | sub disablecache { $cache = 0; } |
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440 | |
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441 | # --- Functions to process the 'time' data type |
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442 | |
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443 | sub new { my @t = (time, times, @_ == 2 ? $_[1] : 0); |
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444 | print STDERR "new=@t\n" if $debug; |
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445 | bless \@t; } |
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446 | |
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447 | sub cpu_p { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps ; } |
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448 | sub cpu_c { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $cu+$cs ; } |
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449 | sub cpu_a { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps+$cu+$cs ; } |
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450 | sub real { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $r ; } |
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451 | sub iters { $_[0]->[5] ; } |
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452 | |
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453 | sub timediff { |
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454 | my($a, $b) = @_; |
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455 | my @r; |
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456 | for (my $i=0; $i < @$a; ++$i) { |
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457 | push(@r, $a->[$i] - $b->[$i]); |
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458 | } |
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459 | bless \@r; |
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460 | } |
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461 | |
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462 | sub timesum { |
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463 | my($a, $b) = @_; |
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464 | my @r; |
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465 | for (my $i=0; $i < @$a; ++$i) { |
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466 | push(@r, $a->[$i] + $b->[$i]); |
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467 | } |
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468 | bless \@r; |
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469 | } |
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470 | |
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471 | sub timestr { |
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472 | my($tr, $style, $f) = @_; |
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473 | my @t = @$tr; |
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474 | warn "bad time value (@t)" unless @t==6; |
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475 | my($r, $pu, $ps, $cu, $cs, $n) = @t; |
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476 | my($pt, $ct, $tt) = ($tr->cpu_p, $tr->cpu_c, $tr->cpu_a); |
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477 | $f = $defaultfmt unless defined $f; |
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478 | # format a time in the required style, other formats may be added here |
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479 | $style ||= $defaultstyle; |
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480 | return '' if $style eq 'none'; |
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481 | $style = ($ct>0) ? 'all' : 'noc' if $style eq 'auto'; |
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482 | my $s = "@t $style"; # default for unknown style |
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483 | $s=sprintf("%2d wallclock secs (%$f usr %$f sys + %$f cusr %$f csys = %$f CPU)", |
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484 | $r,$pu,$ps,$cu,$cs,$tt) if $style eq 'all'; |
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485 | $s=sprintf("%2d wallclock secs (%$f usr + %$f sys = %$f CPU)", |
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486 | $r,$pu,$ps,$pt) if $style eq 'noc'; |
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487 | $s=sprintf("%2d wallclock secs (%$f cusr + %$f csys = %$f CPU)", |
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488 | $r,$cu,$cs,$ct) if $style eq 'nop'; |
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489 | $s .= sprintf(" @ %$f/s (n=$n)", $n / ( $pu + $ps )) if $n && $pu+$ps; |
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490 | $s; |
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491 | } |
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492 | |
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493 | sub timedebug { |
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494 | my($msg, $t) = @_; |
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495 | print STDERR "$msg",timestr($t),"\n" if $debug; |
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496 | } |
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497 | |
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498 | # --- Functions implementing low-level support for timing loops |
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499 | |
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500 | sub runloop { |
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501 | my($n, $c) = @_; |
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502 | |
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503 | $n+=0; # force numeric now, so garbage won't creep into the eval |
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504 | croak "negative loopcount $n" if $n<0; |
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505 | confess "Usage: runloop(number, [string | coderef])" unless defined $c; |
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506 | my($t0, $t1, $td); # before, after, difference |
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507 | |
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508 | # find package of caller so we can execute code there |
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509 | my($curpack) = caller(0); |
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510 | my($i, $pack)= 0; |
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511 | while (($pack) = caller(++$i)) { |
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512 | last if $pack ne $curpack; |
---|
513 | } |
---|
514 | |
---|
515 | my ($subcode, $subref); |
---|
516 | if (ref $c eq 'CODE') { |
---|
517 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; &\$c; } }"; |
---|
518 | $subref = eval $subcode; |
---|
519 | } |
---|
520 | else { |
---|
521 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; $c;} }"; |
---|
522 | $subref = _doeval($subcode); |
---|
523 | } |
---|
524 | croak "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@; |
---|
525 | print STDERR "runloop $n '$subcode'\n" if $debug; |
---|
526 | |
---|
527 | # Wait for the user timer to tick. This makes the error range more like |
---|
528 | # -0.01, +0. If we don't wait, then it's more like -0.01, +0.01. This |
---|
529 | # may not seem important, but it significantly reduces the chances of |
---|
530 | # getting a too low initial $n in the initial, 'find the minimum' loop |
---|
531 | # in &countit. This, in turn, can reduce the number of calls to |
---|
532 | # &runloop a lot, and thus reduce additive errors. |
---|
533 | my $tbase = Benchmark->new(0)->[1]; |
---|
534 | while ( ( $t0 = Benchmark->new(0) )->[1] == $tbase ) {} ; |
---|
535 | &$subref; |
---|
536 | $t1 = Benchmark->new($n); |
---|
537 | $td = &timediff($t1, $t0); |
---|
538 | timedebug("runloop:",$td); |
---|
539 | $td; |
---|
540 | } |
---|
541 | |
---|
542 | |
---|
543 | sub timeit { |
---|
544 | my($n, $code) = @_; |
---|
545 | my($wn, $wc, $wd); |
---|
546 | |
---|
547 | printf STDERR "timeit $n $code\n" if $debug; |
---|
548 | my $cache_key = $n . ( ref( $code ) ? 'c' : 's' ); |
---|
549 | if ($cache && exists $cache{$cache_key} ) { |
---|
550 | $wn = $cache{$cache_key}; |
---|
551 | } else { |
---|
552 | $wn = &runloop($n, ref( $code ) ? sub { } : '' ); |
---|
553 | # Can't let our baseline have any iterations, or they get subtracted |
---|
554 | # out of the result. |
---|
555 | $wn->[5] = 0; |
---|
556 | $cache{$cache_key} = $wn; |
---|
557 | } |
---|
558 | |
---|
559 | $wc = &runloop($n, $code); |
---|
560 | |
---|
561 | $wd = timediff($wc, $wn); |
---|
562 | timedebug("timeit: ",$wc); |
---|
563 | timedebug(" - ",$wn); |
---|
564 | timedebug(" = ",$wd); |
---|
565 | |
---|
566 | $wd; |
---|
567 | } |
---|
568 | |
---|
569 | |
---|
570 | my $default_for = 3; |
---|
571 | my $min_for = 0.1; |
---|
572 | |
---|
573 | |
---|
574 | sub countit { |
---|
575 | my ( $tmax, $code ) = @_; |
---|
576 | |
---|
577 | if ( not defined $tmax or $tmax == 0 ) { |
---|
578 | $tmax = $default_for; |
---|
579 | } elsif ( $tmax < 0 ) { |
---|
580 | $tmax = -$tmax; |
---|
581 | } |
---|
582 | |
---|
583 | die "countit($tmax, ...): timelimit cannot be less than $min_for.\n" |
---|
584 | if $tmax < $min_for; |
---|
585 | |
---|
586 | my ($n, $tc); |
---|
587 | |
---|
588 | # First find the minimum $n that gives a significant timing. |
---|
589 | for ($n = 1; ; $n *= 2 ) { |
---|
590 | my $td = timeit($n, $code); |
---|
591 | $tc = $td->[1] + $td->[2]; |
---|
592 | last if $tc > 0.1; |
---|
593 | } |
---|
594 | |
---|
595 | my $nmin = $n; |
---|
596 | |
---|
597 | # Get $n high enough that we can guess the final $n with some accuracy. |
---|
598 | my $tpra = 0.1 * $tmax; # Target/time practice. |
---|
599 | while ( $tc < $tpra ) { |
---|
600 | # The 5% fudge is to keep us from iterating again all |
---|
601 | # that often (this speeds overall responsiveness when $tmax is big |
---|
602 | # and we guess a little low). This does not noticably affect |
---|
603 | # accuracy since we're not couting these times. |
---|
604 | $n = int( $tpra * 1.05 * $n / $tc ); # Linear approximation. |
---|
605 | my $td = timeit($n, $code); |
---|
606 | my $new_tc = $td->[1] + $td->[2]; |
---|
607 | # Make sure we are making progress. |
---|
608 | $tc = $new_tc > 1.2 * $tc ? $new_tc : 1.2 * $tc; |
---|
609 | } |
---|
610 | |
---|
611 | # Now, do the 'for real' timing(s), repeating until we exceed |
---|
612 | # the max. |
---|
613 | my $ntot = 0; |
---|
614 | my $rtot = 0; |
---|
615 | my $utot = 0.0; |
---|
616 | my $stot = 0.0; |
---|
617 | my $cutot = 0.0; |
---|
618 | my $cstot = 0.0; |
---|
619 | my $ttot = 0.0; |
---|
620 | |
---|
621 | # The 5% fudge is because $n is often a few % low even for routines |
---|
622 | # with stable times and avoiding extra timeit()s is nice for |
---|
623 | # accuracy's sake. |
---|
624 | $n = int( $n * ( 1.05 * $tmax / $tc ) ); |
---|
625 | |
---|
626 | while () { |
---|
627 | my $td = timeit($n, $code); |
---|
628 | $ntot += $n; |
---|
629 | $rtot += $td->[0]; |
---|
630 | $utot += $td->[1]; |
---|
631 | $stot += $td->[2]; |
---|
632 | $cutot += $td->[3]; |
---|
633 | $cstot += $td->[4]; |
---|
634 | $ttot = $utot + $stot; |
---|
635 | last if $ttot >= $tmax; |
---|
636 | |
---|
637 | $ttot = 0.01 if $ttot < 0.01; |
---|
638 | my $r = $tmax / $ttot - 1; # Linear approximation. |
---|
639 | $n = int( $r * $ntot ); |
---|
640 | $n = $nmin if $n < $nmin; |
---|
641 | } |
---|
642 | |
---|
643 | return bless [ $rtot, $utot, $stot, $cutot, $cstot, $ntot ]; |
---|
644 | } |
---|
645 | |
---|
646 | # --- Functions implementing high-level time-then-print utilities |
---|
647 | |
---|
648 | sub n_to_for { |
---|
649 | my $n = shift; |
---|
650 | return $n == 0 ? $default_for : $n < 0 ? -$n : undef; |
---|
651 | } |
---|
652 | |
---|
653 | sub timethis{ |
---|
654 | my($n, $code, $title, $style) = @_; |
---|
655 | my($t, $for, $forn); |
---|
656 | |
---|
657 | if ( $n > 0 ) { |
---|
658 | croak "non-integer loopcount $n, stopped" if int($n)<$n; |
---|
659 | $t = timeit($n, $code); |
---|
660 | $title = "timethis $n" unless defined $title; |
---|
661 | } else { |
---|
662 | $fort = n_to_for( $n ); |
---|
663 | $t = countit( $fort, $code ); |
---|
664 | $title = "timethis for $fort" unless defined $title; |
---|
665 | $forn = $t->[-1]; |
---|
666 | } |
---|
667 | local $| = 1; |
---|
668 | $style = "" unless defined $style; |
---|
669 | printf("%10s: ", $title) unless $style eq 'none'; |
---|
670 | print timestr($t, $style, $defaultfmt),"\n" unless $style eq 'none'; |
---|
671 | |
---|
672 | $n = $forn if defined $forn; |
---|
673 | |
---|
674 | # A conservative warning to spot very silly tests. |
---|
675 | # Don't assume that your benchmark is ok simply because |
---|
676 | # you don't get this warning! |
---|
677 | print " (warning: too few iterations for a reliable count)\n" |
---|
678 | if $n < $min_count |
---|
679 | || ($t->real < 1 && $n < 1000) |
---|
680 | || $t->cpu_a < $min_cpu; |
---|
681 | $t; |
---|
682 | } |
---|
683 | |
---|
684 | sub timethese{ |
---|
685 | my($n, $alt, $style) = @_; |
---|
686 | die "usage: timethese(count, { 'Name1'=>'code1', ... }\n" |
---|
687 | unless ref $alt eq HASH; |
---|
688 | my @names = sort keys %$alt; |
---|
689 | $style = "" unless defined $style; |
---|
690 | print "Benchmark: " unless $style eq 'none'; |
---|
691 | if ( $n > 0 ) { |
---|
692 | croak "non-integer loopcount $n, stopped" if int($n)<$n; |
---|
693 | print "timing $n iterations of" unless $style eq 'none'; |
---|
694 | } else { |
---|
695 | print "running" unless $style eq 'none'; |
---|
696 | } |
---|
697 | print " ", join(', ',@names) unless $style eq 'none'; |
---|
698 | unless ( $n > 0 ) { |
---|
699 | my $for = n_to_for( $n ); |
---|
700 | print ", each" if $n > 1 && $style ne 'none'; |
---|
701 | print " for at least $for CPU seconds" unless $style eq 'none'; |
---|
702 | } |
---|
703 | print "...\n" unless $style eq 'none'; |
---|
704 | |
---|
705 | # we could save the results in an array and produce a summary here |
---|
706 | # sum, min, max, avg etc etc |
---|
707 | my %results; |
---|
708 | foreach my $name (@names) { |
---|
709 | $results{$name} = timethis ($n, $alt -> {$name}, $name, $style); |
---|
710 | } |
---|
711 | |
---|
712 | return \%results; |
---|
713 | } |
---|
714 | |
---|
715 | sub cmpthese{ |
---|
716 | my ($results, $style) = ref $_[0] ? @_ : ( timethese( @_[0,1,2] ), $_[2] ) ; |
---|
717 | |
---|
718 | $style = "" unless defined $style; |
---|
719 | |
---|
720 | # Flatten in to an array of arrays with the name as the first field |
---|
721 | my @vals = map{ [ $_, @{$results->{$_}} ] } keys %$results; |
---|
722 | |
---|
723 | for (@vals) { |
---|
724 | # The epsilon fudge here is to prevent div by 0. Since clock |
---|
725 | # resolutions are much larger, it's below the noise floor. |
---|
726 | my $rate = $_->[6] / ( $_->[2] + $_->[3] + 0.000000000000001 ); |
---|
727 | $_->[7] = $rate; |
---|
728 | } |
---|
729 | |
---|
730 | # Sort by rate |
---|
731 | @vals = sort { $a->[7] <=> $b->[7] } @vals; |
---|
732 | |
---|
733 | # If more than half of the rates are greater than one... |
---|
734 | my $display_as_rate = $vals[$#vals>>1]->[7] > 1; |
---|
735 | |
---|
736 | my @rows; |
---|
737 | my @col_widths; |
---|
738 | |
---|
739 | my @top_row = ( |
---|
740 | '', |
---|
741 | $display_as_rate ? 'Rate' : 's/iter', |
---|
742 | map { $_->[0] } @vals |
---|
743 | ); |
---|
744 | |
---|
745 | push @rows, \@top_row; |
---|
746 | @col_widths = map { length( $_ ) } @top_row; |
---|
747 | |
---|
748 | # Build the data rows |
---|
749 | # We leave the last column in even though it never has any data. Perhaps |
---|
750 | # it should go away. Also, perhaps a style for a single column of |
---|
751 | # percentages might be nice. |
---|
752 | for my $row_val ( @vals ) { |
---|
753 | my @row; |
---|
754 | |
---|
755 | # Column 0 = test name |
---|
756 | push @row, $row_val->[0]; |
---|
757 | $col_widths[0] = length( $row_val->[0] ) |
---|
758 | if length( $row_val->[0] ) > $col_widths[0]; |
---|
759 | |
---|
760 | # Column 1 = performance |
---|
761 | my $row_rate = $row_val->[7]; |
---|
762 | |
---|
763 | # We assume that we'll never get a 0 rate. |
---|
764 | my $a = $display_as_rate ? $row_rate : 1 / $row_rate; |
---|
765 | |
---|
766 | # Only give a few decimal places before switching to sci. notation, |
---|
767 | # since the results aren't usually that accurate anyway. |
---|
768 | my $format = |
---|
769 | $a >= 100 ? |
---|
770 | "%0.0f" : |
---|
771 | $a >= 10 ? |
---|
772 | "%0.1f" : |
---|
773 | $a >= 1 ? |
---|
774 | "%0.2f" : |
---|
775 | $a >= 0.1 ? |
---|
776 | "%0.3f" : |
---|
777 | "%0.2e"; |
---|
778 | |
---|
779 | $format .= "/s" |
---|
780 | if $display_as_rate; |
---|
781 | # Using $b here due to optimizing bug in _58 through _61 |
---|
782 | my $b = sprintf( $format, $a ); |
---|
783 | push @row, $b; |
---|
784 | $col_widths[1] = length( $b ) |
---|
785 | if length( $b ) > $col_widths[1]; |
---|
786 | |
---|
787 | # Columns 2..N = performance ratios |
---|
788 | my $skip_rest = 0; |
---|
789 | for ( my $col_num = 0 ; $col_num < @vals ; ++$col_num ) { |
---|
790 | my $col_val = $vals[$col_num]; |
---|
791 | my $out; |
---|
792 | if ( $skip_rest ) { |
---|
793 | $out = ''; |
---|
794 | } |
---|
795 | elsif ( $col_val->[0] eq $row_val->[0] ) { |
---|
796 | $out = "--"; |
---|
797 | # $skip_rest = 1; |
---|
798 | } |
---|
799 | else { |
---|
800 | my $col_rate = $col_val->[7]; |
---|
801 | $out = sprintf( "%.0f%%", 100*$row_rate/$col_rate - 100 ); |
---|
802 | } |
---|
803 | push @row, $out; |
---|
804 | $col_widths[$col_num+2] = length( $out ) |
---|
805 | if length( $out ) > $col_widths[$col_num+2]; |
---|
806 | |
---|
807 | # A little wierdness to set the first column width properly |
---|
808 | $col_widths[$col_num+2] = length( $col_val->[0] ) |
---|
809 | if length( $col_val->[0] ) > $col_widths[$col_num+2]; |
---|
810 | } |
---|
811 | push @rows, \@row; |
---|
812 | } |
---|
813 | |
---|
814 | return \@rows if $style eq "none"; |
---|
815 | |
---|
816 | # Equalize column widths in the chart as much as possible without |
---|
817 | # exceeding 80 characters. This does not use or affect cols 0 or 1. |
---|
818 | my @sorted_width_refs = |
---|
819 | sort { $$a <=> $$b } map { \$_ } @col_widths[2..$#col_widths]; |
---|
820 | my $max_width = ${$sorted_width_refs[-1]}; |
---|
821 | |
---|
822 | my $total = @col_widths - 1 ; |
---|
823 | for ( @col_widths ) { $total += $_ } |
---|
824 | |
---|
825 | STRETCHER: |
---|
826 | while ( $total < 80 ) { |
---|
827 | my $min_width = ${$sorted_width_refs[0]}; |
---|
828 | last |
---|
829 | if $min_width == $max_width; |
---|
830 | for ( @sorted_width_refs ) { |
---|
831 | last |
---|
832 | if $$_ > $min_width; |
---|
833 | ++$$_; |
---|
834 | ++$total; |
---|
835 | last STRETCHER |
---|
836 | if $total >= 80; |
---|
837 | } |
---|
838 | } |
---|
839 | |
---|
840 | # Dump the output |
---|
841 | my $format = join( ' ', map { "%${_}s" } @col_widths ) . "\n"; |
---|
842 | substr( $format, 1, 0 ) = '-'; |
---|
843 | for ( @rows ) { |
---|
844 | printf $format, @$_; |
---|
845 | } |
---|
846 | |
---|
847 | return \@rows ; |
---|
848 | } |
---|
849 | |
---|
850 | |
---|
851 | 1; |
---|