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  • Committer: John Arbash Meinel
  • Date: 2009-04-16 20:45:41 UTC
  • mto: This revision was merged to the branch mainline in revision 4323.
  • Revision ID: john@arbash-meinel.com-20090416204541-gg2qtfggaxwzudvz
Fairly significant savings... avoid looking at self._last_recently_used.
We can get the same information from node.next_key, which is a value we need anyway.
Somewhat surprisingly, this drops us from 7.6s => 7.1s on 2.8M lookups.

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bzrlib/lru_cache.py
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            return node.value
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        # Remove this node from the old location
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        node_prev = node.prev
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        if node is self._last_recently_used:
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            self._last_recently_used = node_prev
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        next_key = node.next_key
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        node_prev.next_key = next_key
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        if next_key is None:
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            node_next = None
 
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            # 'node' is the _last_recently_used, because it doesn't have a
 
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            # 'next' item. So move the current lru to the previous node.
 
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            self._last_recently_used = node_prev
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        else:
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            node_next = cache[next_key]
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            node_next.prev = node_prev
 
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        node_prev.next_key = next_key
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        # Insert this node at the front of the list
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        node.next_key = mru.key
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        mru.prev = node