| 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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