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Re: RFC - Alternatives to gengtype
On Thu, Nov 22, 2012 at 09:29:43PM +0100, Florian Weimer wrote:
> On 11/18/2012 07:06 PM, NightStrike wrote:
>
> >What's wrong with std::shared_ptr?
>
> The pointer needs two words, and the per-object overhead for the
> reference counts etc. is four words, if I'm counting correctly.
>
> (Other forms of reference counting have less overhead, of course,
> but you were asking about std::shared_ptr.)
Actually, this observation may favor a real garbage collector. Marking GC as simple as ggc+gengtype usually have one (or a few) mark bits, so can consume only a few bits (or perhaps a byte in some mark array) per object. Copying GC could avoid consuming any more storage per object. Of course useless object may stay in memory for a while -until the GC deletes them or reuse their memory- but that observation is also true with traditional C++ "GC" techniques like shared_ptr .... An object may be freed later than what should be possible.
And some GC techniques are quite friendly with L1 or L2 caches on the processor chip.
Regards.
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