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Re: Faster compilation speed
David S. Miller <firstname.lastname@example.org> writes:
> From: Dale Johannesen <email@example.com>
> Date: Wed, 14 Aug 2002 10:17:46 -0700
> And I know this is blindingly obvious, but RC takes an extra field (word,
> probably) in each node. I suspect this is going to eat up a lot of
> whatever gain there might be.
>My implementation (I posted the hacked up infrastructure patch the
>other day) used space which is currently empty alongside a bitfield
>in the rtx.
Yet another speed/space trade-off - most architecures are going to take
significantly longer to inc/dec a bitfield than they will doing
RC is obviously less expensive in space when the "things" are larger,
an extra int is horribly expensive when there are only a few words
in the struct, but harmless when there are thousands.
Which reminds me that one of the advantages of the "obstack" scheme
was it tended to act as a "slab allocator" with relatively few
chunks with lots of little things inside each chunk.