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Internals-DumpArenas-0.12
River stage one • 1 direct dependent • 1 total dependent
/ Internals::DumpArenas

NAME

Internals::DumpArenas - Dump perl memory

DESCRIPTION

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

PERL FUNCTIONS

DumpArenas()

Dumps everything to STDERR.

C FUNCTIONS

DumpArenas(pTHX)

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

DumpArenasFd(pTHX_ int fd)

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

OUTPUT FORMAT

INDIVIDUAL VALUES

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

Arrays

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}}

Hashes

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

Pointers to special addresses are displayed symbolically:

PL_sv_undef
PL_sv_yes
PL_sv_no
PL_sv_placeholder

ARENA MAP

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)

BUGS

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.

SUPPORT

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

perldoc Internals::DumpArenas

You can also look for information at:

ACKNOWLEDGEMENTS

Brian Rice, totally.

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

COPYRIGHT & LICENSE

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.

SOURCE AVAILABILITY

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

AUTHOR

Josh Jore