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Devel::MAT - Perl Memory Analysis Tool



If you are new to the Devel::MAT set of tools, this is probably not the document you want to start with. If you are interested in using Devel::MAT to help diagnose memory-related problems in a perl program you instead want to read the user guide, at Devel::MAT::UserGuide.

If you are writing tooling modules to extend the abilities of Devel::MAT then this may indeed by the document for you; read on...


A Devel::MAT instance loads a heapdump file, and provides a container to store analysis tools to work on it. Tools may be provided that conform to the Devel::MAT::Tool API, which can help analyse the data and interact with the explorer user interface by using the methods in the Devel::MAT::UI package.

File Format

The dump file format is still under development, so at present no guarantees are made on whether files can be loaded over mismatching versions of Devel::MAT. However, as of version 0.11 the format should be more extensible, allowing new SV fields to be added without breaking loading - older tools will ignore new fields and newer tools will just load undef for fields absent in older files. As the distribution approaches maturity the format will be made more stable.



   $pmat = Devel::MAT->load( $path, %args );

Loads a heap dump file from the given path, and returns a new Devel::MAT instance wrapping it.



   $df = $pmat->dumpfile;

Returns the underlying Devel::MAT::Dumpfile instance backing this analysis object.


   @tools = $pmat->available_tools;

Lists the Devel::MAT::Tool classes that are installed and available.


   $tool = $pmat->load_tool( $name );

Loads the named Devel::MAT::Tool class.


   $bool = $pmat->has_tool( $name );

Returns true if the named tool is already loaded.


   $pmat->run_command( $inv );

Runs a tool command given by the Commandable::Invocation instance.


   $node = $pmat->inref_graph( $sv, %opts );

Traces the tree of inrefs from $sv back towards the known roots, returning a Devel::MAT::Graph node object representing it, within a graph of reverse references back to the known roots.

This method will load Devel::MAT::Tool::Inrefs if it isn't yet loaded.

The following named options are recognised:

depth => INT

If specified, stop recursing after the specified count. A depth of 1 will only include immediately referring SVs, 2 will print the referrers of those, etc. Nodes with inrefs that were trimmed because of this limit will appear to be roots with a special name of EDEPTH.

strong => BOOL
direct => BOOL

Specifies the type of inrefs followed. By default all inrefs are followed. Passing strong will follow only strong direct inrefs. Passing direct will follow only direct inrefs.

elide => BOOL

If true, attempt to neaten up the output by skipping over certain structures.

REF()-type SVs will be skipped to their referrant.

Members of the symbol table will be printed as being a 'root' element of the given symbol name.

PADs and PADLISTs will be skipped to their referring CODE, giving shorter output for lexical variables.


   $sv = $pmat->find_symbol( $name );

Attempts to walk the symbol table looking for a symbol of the given name, which must include the sigil.

   $Package::Name::symbol_name => to return a SCALAR SV
   @Package::Name::symbol_name => to return an ARRAY SV
   %Package::Name::symbol_name => to return a HASH SV
   &Package::Name::symbol_name => to return a CODE SV


   $gv = $pmat->find_glob( $name );

Attempts to walk the symbol table looking for a symbol of the given name, returning the GLOB object if found.


   $stash = $pmat->find_stash( $name );

Attempts to walk the symbol table looking for a stash of the given name.


Paul Evans <>