From: Markus Mottl <markus.mottl@gmail.com>
To: Brighten Godfrey <pbg@cs.berkeley.edu>
Cc: Damien Doligez <damien.doligez@inria.fr>,
OCaml List <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] Strange performance bug
Date: Wed, 29 Apr 2009 15:38:53 -0400 [thread overview]
Message-ID: <f8560b80904291238v4a202e23gfda4e4ff0807bc0@mail.gmail.com> (raw)
In-Reply-To: <25CD1992-3F33-4AEA-97A3-EC54729EC4FE@cs.berkeley.edu>
On Wed, Apr 29, 2009 at 15:19, Brighten Godfrey <pbg@cs.berkeley.edu> wrote:
> You seem to have solved my problem. But out of curiosity: Do you know how
> the GC settings in the Str library differ from PCRE's, and why? Why does
> PCRE need to explicitly trigger GCs at all?
Str regular expressions are pure OCaml-values, whereas PCRE regexps
are allocated on the C-heap. Since C-heap values need to be
deallocated explicitly, a finalizer has to be installed that does the
job if the OCaml-value is not reachable anymore. The OCaml-runtime
needs hints about how large these C-values are. Otherwise it may not
scan the OCaml-heap aggressively enough, leaving a lot of those
C-values floating around and eating up your memory.
Right now the PCRE-library guarantees that not more than 500 regular
expressions will float around at any one time. This can lead to
considerable slowdowns if your OCaml-heap is large and you allocate
regular expressions at very high rates.
Regards,
Markus
--
Markus Mottl http://www.ocaml.info markus.mottl@gmail.com
next prev parent reply other threads:[~2009-04-29 19:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-29 2:43 Brighten Godfrey
2009-04-29 3:37 ` [Caml-list] " Markus Mottl
2009-04-29 4:31 ` Brighten Godfrey
2009-04-29 6:18 ` Alain Frisch
2009-04-29 6:27 ` Brighten Godfrey
2009-04-29 6:37 ` Alain Frisch
2009-04-29 8:29 ` Brighten Godfrey
2009-04-29 13:58 ` Markus Mottl
2009-04-29 14:48 ` Damien Doligez
2009-04-29 16:03 ` Markus Mottl
2009-04-29 19:19 ` Brighten Godfrey
2009-04-29 19:38 ` Markus Mottl [this message]
2009-04-29 20:23 ` Brighten Godfrey
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