1 | #!/usr/bin/env python2
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2 | """
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3 | heap_growth.py
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4 | """
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5 | from __future__ import print_function
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6 |
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7 | import sys
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8 |
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9 |
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10 | class Space(object):
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11 | def __init__(self, space_size):
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12 | self.filled_size = 0
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13 | self.space_size = space_size
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14 |
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15 |
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16 | def Simulate(spaces, alloc_sizes):
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17 | # TODO:
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18 | # - how to simulate garbage too
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19 | # - simulate semi-spaces
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20 | # - eventually we could TIGHTEN the heap? Actually we might get that for
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21 | # free?
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22 |
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23 | # Input:
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24 | # - Stream of Allocation Sizes
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25 | # Output:
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26 | # - Whether we should collect now
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27 | # - this happens as rarely as possible, only when we have no space
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28 | # - Whether we should grow, and HOW MUCH (2x, 4x)
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29 | # - this happens AFTER a collection, if we don't have much space left
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30 | # - And we try to keep the sizes even
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31 |
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32 | space = spaces[0]
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33 |
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34 | for i, a in enumerate(alloc_sizes):
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35 | if space.filled_size + a > space.space_size:
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36 | do_collect = True
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37 | else:
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38 | do_collect = False
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39 |
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40 | # Assume we didn't collect anything
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41 | while float(space.filled_size) / space.space_size >= 0.8:
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42 | space.space_size *= 2
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43 |
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44 | space.filled_size += a
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45 |
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46 | yield a, space.filled_size, space.space_size, do_collect
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47 |
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48 |
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49 | def main(argv):
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50 | initial_size = 256
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51 | spaces = [Space(initial_size), Space(initial_size)]
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52 |
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53 | fmt = '%10s %10s %10s %10s'
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54 | print(fmt % ('alloc', 'filled', 'space max', 'collect'))
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55 |
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56 | #alloc_sizes = range(50, 100)
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57 | alloc_sizes = range(0, 10000, 400) # big allocations
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58 | for row in Simulate(spaces, alloc_sizes):
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59 | print(fmt % row)
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60 |
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61 |
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62 | if __name__ == '__main__':
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63 | try:
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64 | main(sys.argv)
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65 | except RuntimeError as e:
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66 | print('FATAL: %s' % e, file=sys.stderr)
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67 | sys.exit(1)
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