From: ludo@gnu.org (Ludovic Courtès)
To: guile-devel@gnu.org
Subject: Optimizing vlists
Date: Mon, 13 Aug 2012 18:47:16 +0200 [thread overview]
Message-ID: <87wr1220yz.fsf_-_@gnu.org> (raw)
In-Reply-To: 5024F643.8040706@netris.org
Hello,
Mark H Weaver <mhw@netris.org> skribis:
> Here's one specific data structure idea: we have a "vlist" data
> structure, currently written in Scheme, but in my opinion it would be
> useful to rewrite it in C for better efficiency.
FWIW, I’m not convinced that this is a fruitful approach.
First, because Guile 2.0 has allowed us to write more things in Scheme,
and I’d like to keep it this way. ;-)
Second, because a very important optimizations would rather be to fiddle
with the GC so that vlists, which are base + offset pairs, would not
have to be heap-allocated, as vlist.scm says:
;; XXX: Allocating a <vlist> record in addition to the block at each
;; `vlist-cons' call is inefficient. However, Bagwell's hack to avoid it
;; (Section 2.2) would require GC_ALL_INTERIOR_POINTERS, which would be a
;; performance hit for everyone.
I remember Andy did some measurements showing that ‘vhash-assoc’ was
often high in the profile when running the compiler. One thing that
could be done is to run a C-level profiler to see exactly what’s going
on, and which optimizations could help.
WDYT?
Thanks,
Ludo’.
next prev parent reply other threads:[~2012-08-13 16:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-06 14:50 a passionate guy who want to join in as a developer rushan chen
2012-08-10 11:53 ` Mark H Weaver
2012-08-12 14:31 ` rushan chen
2012-08-13 10:18 ` nalaginrut
2012-08-13 10:41 ` Tristan Colgate
2012-08-13 15:47 ` rushan chen
2012-08-13 16:47 ` Ludovic Courtès [this message]
2012-12-13 8:58 ` Abhinav Jauhri
2012-12-13 15:31 ` Ludovic Courtès
2012-12-13 23:32 ` Abhinav Jauhri
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