Re: perl memory use question

My test says it takes about 200Mb for a single-linked list.

If you don't need linked lists, using plain arrays is probably more memory efficient.

#!perl/bin/perl 
use strict; 
$|=1;

my ($list1,$list2);
print "Making list1\n";
for (0 .. 1_000_000) {
    my $head = $list1;
    $list1 = ["a" x 40,\$head];
}
print "Making list2\n";
for (0 .. 60_000) {
    my $head = $list2;
    $list2 = ["b" x 338,\$head];
}
print "Press enter to exit: ";

my $dummy = <STDIN>;
[download]

update: perl should be fine with that kind of usage. just remember that perl is no where near as memory-efficient as C can be. perl values have a significant overhead. especially if you have many small objects.

update 2: i get a segfault from this script at destruction. that's not right. (tested perl 5.00504 & perl 5.8.8)

update 3: ok, increasing the stack size limit (ulimit -s 400000) fixes the problem.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

Comment on Re: perl memory use question Download Code

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Re^2: perl memory use question by liverpole (Monsignor) on Jun 03, 2007 at 20:53 UTC
Joost, For fun, I tried running your program on ASP (version 5.8.8, Binary build 819), and got a software exception. That's not to say it's anything with your program of course, I'm sure it's just my memory configuration. I narrowed it down to: `#!perl/bin/perl use strict; use warnings; $\|=1; my ($list1); print "Making list1\n"; for (0 .. 93132) { my $head = $list1; $list1 = ["a" x 40,\$head]; }` [download] which does give the error. When `93132` is changed to `93131`, the error does NOT occur. This is with Windows XP, and 512 MB of RAM. s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/	[reply] [d/l] [select]
Re^3: perl memory use question by Joost (Canon) on Jun 03, 2007 at 21:01 UTC
Warning: untested advice follows. On windows you apparently must edit the binary (i.e. perl.exe) to increase stack size. You can use editbin for that. See for example http://support.microsoft.com/kb/160683 "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]
Re^2: perl memory use question by exodist (Monk) on Jun 03, 2007 at 22:08 UTC
how do I use ulimit/ set the stack size? is it a flag when I run the script, or is it a line in the script?	[reply]
Re^3: perl memory use question by Joost (Canon) on Jun 03, 2007 at 22:57 UTC
ulimit is a bash/sh command that sets various limits for child processes, including the stack size. So you need to set it from the parent process before running the perl script. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]