Re: How do I unpack Perl floats in C

in reply to How do I unpack Perl floats in C

Are you sure the unpack is the bottleneck?

Running the following snippet on my pretty average hardware does around 800_000 unpacks per second.

my $buf = pack "FFFFL", (0.1) x 4, 999;

for (1..1000_000) {
    my @row = unpack "FFFFL", $buf;
}

__END__
$ time ./836298.pl

real    0m1.286s
user    0m1.280s
sys     0m0.004s
[download]

I'd wager an XS routine doing the same wouldn't really be a lot faster...

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Re^2: How do I unpack Perl floats in C by Anonymous Monk on Apr 22, 2010 at 18:58 UTC
According to the profiler that I used, out of a 2 minuite execution time, bout 30 seconds is spent in calls to unpack.	[reply]
Re^3: How do I unpack Perl floats in C by ikegami (Patriarch) on Apr 22, 2010 at 19:30 UTC
So 20,000,000 million records? What do you do with the results of the unpack? You'll need to reimplement more than just a single opcode to get a benefit.	[reply]

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