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      1 '''
      2 Created on May 19, 2011
      3 
      4 @author: bungeman
      5 '''
      6 
      7 import re
      8 import math
      9 
     10 # bench representation algorithm constant names
     11 ALGORITHM_AVERAGE = 'avg'
     12 ALGORITHM_MEDIAN = 'med'
     13 ALGORITHM_MINIMUM = 'min'
     14 ALGORITHM_25TH_PERCENTILE = '25th'
     15 
     16 class BenchDataPoint:
     17     """A single data point produced by bench.
     18 
     19     (str, str, str, float, {str:str})"""
     20     def __init__(self, bench, config, time_type, time, settings):
     21         self.bench = bench
     22         self.config = config
     23         self.time_type = time_type
     24         self.time = time
     25         self.settings = settings
     26 
     27     def __repr__(self):
     28         return "BenchDataPoint(%s, %s, %s, %s, %s)" % (
     29                    str(self.bench),
     30                    str(self.config),
     31                    str(self.time_type),
     32                    str(self.time),
     33                    str(self.settings),
     34                )
     35 
     36 class _ExtremeType(object):
     37     """Instances of this class compare greater or less than other objects."""
     38     def __init__(self, cmpr, rep):
     39         object.__init__(self)
     40         self._cmpr = cmpr
     41         self._rep = rep
     42 
     43     def __cmp__(self, other):
     44         if isinstance(other, self.__class__) and other._cmpr == self._cmpr:
     45             return 0
     46         return self._cmpr
     47 
     48     def __repr__(self):
     49         return self._rep
     50 
     51 Max = _ExtremeType(1, "Max")
     52 Min = _ExtremeType(-1, "Min")
     53 
     54 class _ListAlgorithm(object):
     55     """Algorithm for selecting the representation value from a given list.
     56     representation is one of the ALGORITHM_XXX representation types."""
     57     def __init__(self, data, representation=None):
     58         if not representation:
     59             representation = ALGORITHM_AVERAGE  # default algorithm
     60         self._data = data
     61         self._len = len(data)
     62         if representation == ALGORITHM_AVERAGE:
     63             self._rep = sum(self._data) / self._len
     64         else:
     65             self._data.sort()
     66             if representation == ALGORITHM_MINIMUM:
     67                 self._rep = self._data[0]
     68             else:
     69                 # for percentiles, we use the value below which x% of values are
     70                 # found, which allows for better detection of quantum behaviors.
     71                 if representation == ALGORITHM_MEDIAN:
     72                     x = int(round(0.5 * self._len + 0.5))
     73                 elif representation == ALGORITHM_25TH_PERCENTILE:
     74                     x = int(round(0.25 * self._len + 0.5))
     75                 else:
     76                     raise Exception("invalid representation algorithm %s!" %
     77                                     representation)
     78                 self._rep = self._data[x - 1]
     79 
     80     def compute(self):
     81         return self._rep
     82 
     83 def _ParseAndStoreTimes(config_re, time_re, line, bench, dic,
     84                         representation=None):
     85     """Parses given bench time line with regex and adds data to the given dic.
     86     config_re: regular expression for parsing the config line.
     87     time_re: regular expression for parsing bench time.
     88     line: input string line to parse.
     89     bench: name of bench for the time values.
     90     dic: dictionary to store bench values. See bench_dic in parse() below.
     91     representation: should match one of the ALGORITHM_XXX types."""
     92 
     93     for config in re.finditer(config_re, line):
     94         current_config = config.group(1)
     95         if config_re.startswith('  tile_'):  # per-tile bench, add name prefix
     96             current_config = 'tile_' + current_config
     97         times = config.group(2)
     98         for new_time in re.finditer(time_re, times):
     99             current_time_type = new_time.group(1)
    100             iters = [float(i) for i in
    101                      new_time.group(2).strip().split(',')]
    102             dic.setdefault(bench, {}).setdefault(current_config, {}).setdefault(
    103                 current_time_type, []).append(_ListAlgorithm(
    104                     iters, representation).compute())
    105 
    106 def parse(settings, lines, representation=None):
    107     """Parses bench output into a useful data structure.
    108 
    109     ({str:str}, __iter__ -> str) -> [BenchDataPoint]
    110     representation is one of the ALGORITHM_XXX types."""
    111 
    112     benches = []
    113     current_bench = None
    114     bench_dic = {}  # [bench][config][time_type] -> [list of bench values]
    115     setting_re = '([^\s=]+)(?:=(\S+))?'
    116     settings_re = 'skia bench:((?:\s+' + setting_re + ')*)'
    117     bench_re = 'running bench (?:\[\d+ \d+\] )?\s*(\S+)'
    118     time_re = '(?:(\w*)msecs = )?\s*((?:\d+\.\d+)(?:,\d+\.\d+)*)'
    119     # non-per-tile benches have configs that don't end with ']'
    120     config_re = '(\S+[^\]]): ((?:' + time_re + '\s+)+)'
    121     # per-tile bench lines are in the following format. Note that there are
    122     # non-averaged bench numbers in separate lines, which we ignore now due to
    123     # their inaccuracy.
    124     tile_re = ('  tile_(\S+): tile \[\d+,\d+\] out of \[\d+,\d+\] <averaged>:'
    125                ' ((?:' + time_re + '\s+)+)')
    126 
    127     for line in lines:
    128 
    129         # see if this line is a settings line
    130         settingsMatch = re.search(settings_re, line)
    131         if (settingsMatch):
    132             settings = dict(settings)
    133             for settingMatch in re.finditer(setting_re, settingsMatch.group(1)):
    134                 if (settingMatch.group(2)):
    135                     settings[settingMatch.group(1)] = settingMatch.group(2)
    136                 else:
    137                     settings[settingMatch.group(1)] = True
    138 
    139         # see if this line starts a new bench
    140         new_bench = re.search(bench_re, line)
    141         if new_bench:
    142             current_bench = new_bench.group(1)
    143 
    144         # add configs on this line to the bench_dic
    145         if current_bench:
    146             for regex in [config_re, tile_re]:
    147                  _ParseAndStoreTimes(regex, time_re, line, current_bench,
    148                                      bench_dic, representation)
    149 
    150     # append benches to list, use the total time as final bench value.
    151     for bench in bench_dic:
    152         for config in bench_dic[bench]:
    153             for time_type in bench_dic[bench][config]:
    154                 benches.append(BenchDataPoint(
    155                     bench,
    156                     config,
    157                     time_type,
    158                     sum(bench_dic[bench][config][time_type]),
    159                     settings))
    160 
    161     return benches
    162 
    163 class LinearRegression:
    164     """Linear regression data based on a set of data points.
    165 
    166     ([(Number,Number)])
    167     There must be at least two points for this to make sense."""
    168     def __init__(self, points):
    169         n = len(points)
    170         max_x = Min
    171         min_x = Max
    172 
    173         Sx = 0.0
    174         Sy = 0.0
    175         Sxx = 0.0
    176         Sxy = 0.0
    177         Syy = 0.0
    178         for point in points:
    179             x = point[0]
    180             y = point[1]
    181             max_x = max(max_x, x)
    182             min_x = min(min_x, x)
    183 
    184             Sx += x
    185             Sy += y
    186             Sxx += x*x
    187             Sxy += x*y
    188             Syy += y*y
    189 
    190         denom = n*Sxx - Sx*Sx
    191         if (denom != 0.0):
    192             B = (n*Sxy - Sx*Sy) / denom
    193         else:
    194             B = 0.0
    195         a = (1.0/n)*(Sy - B*Sx)
    196 
    197         se2 = 0
    198         sB2 = 0
    199         sa2 = 0
    200         if (n >= 3 and denom != 0.0):
    201             se2 = (1.0/(n*(n-2)) * (n*Syy - Sy*Sy - B*B*denom))
    202             sB2 = (n*se2) / denom
    203             sa2 = sB2 * (1.0/n) * Sxx
    204 
    205 
    206         self.slope = B
    207         self.intercept = a
    208         self.serror = math.sqrt(max(0, se2))
    209         self.serror_slope = math.sqrt(max(0, sB2))
    210         self.serror_intercept = math.sqrt(max(0, sa2))
    211         self.max_x = max_x
    212         self.min_x = min_x
    213 
    214     def __repr__(self):
    215         return "LinearRegression(%s, %s, %s, %s, %s)" % (
    216                    str(self.slope),
    217                    str(self.intercept),
    218                    str(self.serror),
    219                    str(self.serror_slope),
    220                    str(self.serror_intercept),
    221                )
    222 
    223     def find_min_slope(self):
    224         """Finds the minimal slope given one standard deviation."""
    225         slope = self.slope
    226         intercept = self.intercept
    227         error = self.serror
    228         regr_start = self.min_x
    229         regr_end = self.max_x
    230         regr_width = regr_end - regr_start
    231 
    232         if slope < 0:
    233             lower_left_y = slope*regr_start + intercept - error
    234             upper_right_y = slope*regr_end + intercept + error
    235             return min(0, (upper_right_y - lower_left_y) / regr_width)
    236 
    237         elif slope > 0:
    238             upper_left_y = slope*regr_start + intercept + error
    239             lower_right_y = slope*regr_end + intercept - error
    240             return max(0, (lower_right_y - upper_left_y) / regr_width)
    241 
    242         return 0
    243 
    244 def CreateRevisionLink(revision_number):
    245     """Returns HTML displaying the given revision number and linking to
    246     that revision's change page at code.google.com, e.g.
    247     http://code.google.com/p/skia/source/detail?r=2056
    248     """
    249     return '<a href="http://code.google.com/p/skia/source/detail?r=%s">%s</a>'%(
    250         revision_number, revision_number)
    251 
    252 def main():
    253     foo = [[0.0, 0.0], [0.0, 1.0], [0.0, 2.0], [0.0, 3.0]]
    254     LinearRegression(foo)
    255 
    256 if __name__ == "__main__":
    257     main()
    258