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Re: [BDW-GC] "Inlined" storage; `scm_take_' functions
From: |
Neil Jerram |
Subject: |
Re: [BDW-GC] "Inlined" storage; `scm_take_' functions |
Date: |
Wed, 09 Sep 2009 00:54:13 +0100 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) |
address@hidden (Ludovic Courtès) writes:
> Hello!
Hi!
> Stringbufs and bytevectors are now always "inlined" in the BDW-GC
> branch [0, 1], which means that there's no cell->buffer indirection,
> which greatly simplifies code (it also takes less room and may slightly
> improve performance).
>
> The `scm_take_' functions for strings/symbols/bytevectors are now
> essentially aliases to the corresponding `scm_from_' because we cannot
> advantageously reuse the provided storage.
That seems a bit of a shame. (i.e. that we can't advantageously keep
the caller's string or vector data)
Did you consider the option of
- always having an indirection from the stringbuf/bytevector object to
the underlying data
- optimizing the scm_from_... case by doing a single
scm_gc_malloc_pointerless (), and making the "underlying data
pointer" point into the same malloc'd block.
The first point should allow a similar simplification of the code as
you have in your commits - by not having to handle both the inline and
indirected cases everywhere - but the indirection would allow us to
keep meaningful scm_take_... functions.
Neil