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Re^6: Why it takes so much time here?

by PerlOnTheWay (Scribe)
on Dec 28, 2011 at 04:51 UTC ( #945283=note: print w/replies, xml ) Need Help??

in reply to Re^5: Why it takes so much time here?
in thread Why it takes so much time here?

The same number of int takes less than 1 second to initialize

Isn't 15 secs too much time even though a scalar requires more storage(16 bytes after test) than int?

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Re^7: Why it takes so much time here?
by ikegami (Pope) on Dec 28, 2011 at 05:19 UTC

    The same number of int takes less than 1 second to initialize

    What does that mean?

      So the amount of time is close for the same amount of iteration whether in c or perl.

      My original question still remains,right?

        Ah, compared to C. Well, let's get some numbers.

        $ cat my @a = 1..1_000_000; $ time perl real 0m0.372s user 0m0.276s sys 0m0.092s
        $ cat a.c #include <malloc.h> int main() { int ** array = (int**)malloc(1000000 * sizeof(int*)); int i; for (i = 100000; i--; ) { array[i] = (int*)malloc(sizeof(int)); } for (i = 100000; i--; ) { free(array[i]); } free(array); return 0; } $ time a real 0m0.014s user 0m0.012s sys 0m0.000s

        (Did a couple of runs of both and picked a representative time.)

        Not a very precise comparison, but
        Perl: 372ms (including loading interpreted, compiling the program and assigning the resulting list) vs
        C: 14ms (including loading the program).

        (For one million.)

        Where do you get 15s?! I don't see this slowdown.

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