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Re^2: threads::shared variables not really shared... or are they?

by renodino (Curate)
on Mar 08, 2008 at 03:21 UTC ( #672931=note: print w/ replies, xml ) Need Help??


in reply to Re: threads::shared variables not really shared... or are they?
in thread threads::shared variables not really shared... or are they?

The original added 100 1Mbyte strings to @a. Your example adds 50 * 10 = 500 1Mbyte strings to @a. Also, each thread will create a 1Mbyte private scalar; the original only created a single big string.

(The lack of locks is a bit troubling, but the aforementioned global interpretter lock is probably keeping your example out of trouble)


Perl Contrarian & SQL fanboy


Comment on Re^2: threads::shared variables not really shared... or are they?
Re^3: threads::shared variables not really shared... or are they?
by zentara (Archbishop) on Mar 08, 2008 at 18:47 UTC
    Ooops, you are right, this one gives memory use that agrees with the OP's original script. I think the sleep calls prevent the locking problem. At least on a faster machine. :-)
    #!/usr/bin/perl use threads; use threads::shared; my @a : shared; for (1..10) { sleep 1; threads->new(\&foo); } sleep 1; system "grep VmSize /proc/$$/status"; <>; sub foo { for (1..10) { push @a, " " x 1e6; } print @a . " elements in \@a\n"; }

    I'm not really a human, but I play one on earth. Cogito ergo sum a bum

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