http://qs321.pair.com?node_id=846678

I always wanted to know memory usage of particular structure in my perl programs. Recently, I noticed that Storable file size corresponds nicely to memory usage of my application, so I used that as a hint of memory usage before loading data.

Then, I decided to show usage of already loaded data. Using Devel::Size total_size seemed like the way to go, but it's much slower than simple Storable piping to /dev/null

Rate total_size storable total_size 4.04/s -- -70% storable 13.5/s 234% --
using this code
use Benchmark qw(:all); use Devel::Size; use Storable; sub _storable_size { open(my $fh, '|-', 'cat > /dev/null'); Storable::store_fd $_[0], $fh; tell($fh); } my $o; $o->{$_} = rand() foreach ( 'a' .. 'z' ); my $hash; $hash->{$_} = $o foreach ( 0 .. 100_000 ); cmpthese( 100, { 'total_size' => sub { Devel::Size::total_size( $hash ) }, 'storable' => sub { _storable_size( $hash ) }, });
To be honest, I didn't expect so much difference. I can probably setup pipes myself to get a bit more performance, but I would really like to know alternative ways to find out perl memory usage without performance impact.

I'm experimenting with this code in gist on github as a log of things that I tried.


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