From: Abhijeet More <abhijeet.more@gmail.com>
To: guile-user@gnu.org
Subject: Possible Memory Leak with stream-for-each
Date: Mon, 19 Jul 2010 14:08:45 -0400 [thread overview]
Message-ID: <AANLkTinCvRboQ6IqBBPOL5Mz0vz5XPx0J9AQf2dnDNXJ@mail.gmail.com> (raw)
Hi All,
I've been trying to use streams as defined in SICP using guile.
A little googling showed that an implementation had already been suggested here:
http://lists.gnu.org/archive/html/guile-user/2001-04/msg00220.html
However, when I use this to iterate through the stream I see that
guile's memory utilization keeps growing until the iteration is
complete . I'm using guile 1.6.8 (also tested 1.8.7) on linux. I
observe the memory utilization under top.
I tried the same thing with plt-scheme/racket and it did not show a
similar leak i.e .the memory growth was capped at a certain point
during the iteration. It did not grow beyond that point.
From a little more googling, it appears that a similar memory leak has
been discussed before but that investigation was not completed. Here
is the thread:
http://sources.redhat.com/ml/guile/2000-03/msg00568.html
So my questions are:
1. Can it be confirmed that this is a leak in guile's garbage collection?
2. Are there any workarounds (for instance doing an explicit "(gc)"
somewhere in the definitions?
3. Any pointers on fixing the underlying issue?
4. I noticed that streams in guile (ice-9 streams) were not
implemented in the SICP way. In-fact they were implemented in a way
that makes recursive definitions impossible. Was this intentional?
Some code to illustrate what I'm trying to do:
Simply print all s-expressions in a file to another as follows :
(let* ((outport (open-output-file <OUT-FILE-NAME>)))
(stream-for-each (lambda (x) (pretty-print x outport))
(port->stream (open-input-file <IN-FILE-NAME>) read)))
where port->stream is:
(define (port->stream port readproc)
(cons-stream (readproc port) (port->stream port readproc)))
(defmacro cons-stream (a b)
`(cons ,a (delay ,b)))
(define stream-null? null?)
(define the-empty-stream '())
(define (stream-car stream) (car stream))
(define (stream-cdr stream) (force (cdr stream)))
(define (stream-for-each proc s)
(if (not (stream-null? s))
(begin (proc (stream-car s))
(stream-for-each proc (stream-cdr s)))))
I get the same behavior with the following definition:
(define-syntax cons-stream
(syntax-rules ()
((_ ?car ?cdr) (cons ?car (delay ?cdr)))))
Thanks
Abhijeet
next reply other threads:[~2010-07-19 18:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-19 18:08 Abhijeet More [this message]
2010-07-20 20:36 ` Possible Memory Leak with stream-for-each Andy Wingo
2010-07-21 7:00 ` Tristan Colgate
2010-07-24 16:13 ` Ludovic Courtès
2010-07-24 16:32 ` Abhijeet More
2010-07-24 16:46 ` Abhijeet More
2010-07-26 9:36 ` Andy Wingo
2010-07-30 0:38 ` Abhijeet More
2010-07-31 11:48 ` Andy Wingo
2010-07-31 20:16 ` Abhijeet More
2010-08-11 16:57 ` Abhijeet More
2010-08-02 3:29 ` Tibi Turbureanu
2010-08-15 15:12 ` Heap profiler Ludovic Courtès
2010-09-02 12:49 ` Possible Memory Leak with stream-for-each Ludovic Courtès
2010-09-02 16:20 ` Julian Graham
2010-09-02 18:46 ` Andy Wingo
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