Devel::Arena - Perl extension for inspecting the core's arena structures
use Devel::Arena 'sv_stats'; # Get hash ref describing the arenas for SV heads $sv_stats = sv_stats;
Inspect the arena structures that perl uses for SV allocation.
HARNESS_PERL_SWITCHES=-MDevel::Arena=write_stats_at_END make test
None by default.
sv_stats [DONT_SHARE]
Returns a hashref giving stats derived from inspecting the SV heads via the arena pointers. Details of the contents of the hash subject to change.
If the optional argument DONT_SHARE is true then none of the hashes in the returned structure have shared hash keys. This is less efficient, but is needed to calculate the effectiveness of the shared string table.
shared_string_table
Returns a hashref giving the share counts for each entry in the shared string table. The hashref doesn't use shared keys itself, so it doesn't affect the thing that it is measuring.
sizes
Returns a hashref containing sizes of various core perl types, C types, and other size related info (specifically 'hek_key offset')
HEK_size STRING
Calculates the size of the hash key needed to store STRING.
shared_string_table_effectiveness
Calculates the effectiveness of the shared string table. Returns a hashref of stats. Currently this is
{ 'pv_unshared' => 7185, 'raw_unshared' => 77264, 'heks' => 3748, 'pv_hv' => 77264, 'hv_unshared' => 70079, 'raw_shared' => 57675, 'pvs' => 434, 'raw' => 1833 };
It ignores malloc() overhead, and the possibility that some shared strings aren't used as hash keys or shared hash key scalars.
write_stats_at_END
Not really a function, but if you import write_stats_at_END then Devel::Arena will write out a Storable dump of all stats at END time. The file is written into a file into a file in the current directory named $$ . '.sv_stats'. This allows you to do things such as
END
$$ . '.sv_stats'
to analyse the resource usage in regression tests.
sv.c in the perl core.
Nicholas Clark, <nick@ccl4.org>
Copyright (C) 2005, 2006 by Nicholas Clark
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.
To install Devel::Arena, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Devel::Arena
CPAN shell
perl -MCPAN -e shell install Devel::Arena
For more information on module installation, please visit the detailed CPAN module installation guide.