A couple garbage collector questions
Skip Montanaro
skip at pobox.com
Thu Apr 5 13:34:52 EDT 2001
>>> Reference-counting exacts very heavy performance costs, no matter
>>> what you back it up with.
Hannah> Correct. *Except* if the compiler does heavy optimization of
Hannah> reference count updates (i.e. if you can prove that some basic
Hannah> block just increases the RC, later decreases it, having a net
Hannah> effect of +- 0, you can drop both RC updates, and so on).
This is unlikely to happen in practice. A basic block consists of a
straightline piece of code containing no branches. There's no reason to
increment a reference count and decrement it within the same basic block,
since the object's reference count can't be decremented to zero by some
other piece of code.
--
Skip Montanaro (skip at pobox.com)
(847)971-7098
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