Internals::DumpArenas - Dump perl memory

Dumps all of perl's regular values. This iterates over all values reachable by the perl's normal memory management.

Dumps everything to STDERR.

A C-exportable function. This calls DumpArenasFd but defaults to printing to STDERR. Depending on whether your perl interpreter is threaded, accepts the interpreter context.

From gdb:

    set $context = Perl_get_context()
    if $context
        call DumpArenas($context)
    else
        call DumpArenas()
    end

An exportable function, and the basis for DumpArenas(). The fd parameter is the file descriptor to write to. This lets you choose to write to stdout or something else convenient.

Like the above function, this also accepts the interpreter context as an argument for threaded perl.

From gdb:

    set $context = Perl_get_context()
    if $context
        # stdout: 1
        # stderr: 2
        call DumpArenasFd($context, 1)
    else
        call DumpArenasFd(1)
    end

At a basic level, each and every perl value is printed using the same facility as the core function Devel::Peek::Dump. This is a low-level, verbose way of describing perl values:

  use Devel::Peek;
  Dump("Hello world!\n");
  Dump(42);

produces the following output. You can see the values "Hello world!\n" and 42 but also other details of perl's implementation.

  SV = PV(0x9919128) at 0x992a7d8
    REFCNT = 1
    FLAGS = (POK,READONLY,pPOK)
    PV = 0x992f638 "Hello world!\n"\0
    CUR = 13
    LEN = 16
  SV = IV(0x992a7f4) at 0x992a7f8
    REFCNT = 1
    FLAGS = (IOK,READONLY,pIOK)
    IV = 42

Array containers also consume space and hold pointers to perl values. The general format is:

  AvARRAY(0x1123e150) = {address,address ...}

Arrays which have more entries allocated than used will show a doubled-up entry with the "extra" part being visible at the end. The general format is:

  AvARRAY(0x1117f3c0) = {{addresses}{addresses}}

and a specific example:

  AvARRAY(0x1117f3c0) = {{0x104a7b98,PL_sv_undef,PL_sv_undef}{PL_sv_undef}}

Hash containers also consume space and hold pointers to perl values. The general format is:

  HvARRAY(address)
    [address "key value"] => address
    [address "key value"] => address
    ...

A specific example:

  ARRAY(0x1123e1e0)
    [0x814a7c0 "_percentage"] => 0x104d5b78
    [0x814a840 "_description"] => 0x104d5b90
    [0x814a780 "_treatment_id"] => 0x104d5b60

Pointers to special addresses are displayed symbolically:

PL_sv_undef

PL_sv_yes

PL_sv_no

PL_sv_placeholder

Each arena map is also printed as work is begun and finished.

  START ARENA = (0xfe4f360-0x1004f340)
  ...
  END ARENA = (0xfe4f360-0x1004f340)

Empty slots in the arena maps are printed as:

  AVAILABLE(0x10abf758)

Please report any bugs or feature requests to bug-Internals-DumpArenas at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Internals-DumpArenas. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

You can find documentation for this module with the perldoc command.

  perldoc Internals::DumpArenas

You can also look for information at:

* RT: CPAN's request tracker

http://rt.cpan.org/NoAuth/Bugs.html?Dist=Internals-DumpArenas

* AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/Internals-DumpArenas

* CPAN Ratings

http://cpanratings.perl.org/d/Internals-DumpArenas

* Search CPAN

http://search.cpan.org/dist/Internals-DumpArenas/

Brian Rice, totally.

I was inspired by http://netjam.org/spoon/viz/ and want to make the same thing for perl.

Copyright 2009-2011 Josh Jore, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

This source is in Github: git://github.com/jbenjore/internals-dumparenas.git

Josh Jore