package Devel::Peek;
-$VERSION = $VERSION = 0.95;
+# Underscore to allow older Perls to access older version from CPAN
+$VERSION = '1.00_01';
require Exporter;
-require DynaLoader;
+use XSLoader ();
-@ISA = qw(Exporter DynaLoader);
-@EXPORT = qw(Dump mstat DeadCode DumpArray DumpWithOP DumpProg);
-@EXPORT_OK = qw(SvREFCNT SvREFCNT_inc SvREFCNT_dec);
+@ISA = qw(Exporter);
+@EXPORT = qw(Dump mstat DeadCode DumpArray DumpWithOP DumpProg
+ fill_mstats mstats_fillhash mstats2hash);
+@EXPORT_OK = qw(SvREFCNT SvREFCNT_inc SvREFCNT_dec CvGV);
%EXPORT_TAGS = ('ALL' => [@EXPORT, @EXPORT_OK]);
-bootstrap Devel::Peek;
+XSLoader::load 'Devel::Peek';
sub DumpWithOP ($;$) {
local($Devel::Peek::dump_ops)=1;
function.
Function C<DumpArray()> allows dumping of multiple values (useful when you
-need to analize returns of functions).
+need to analyze returns of functions).
The global variable $Devel::Peek::pv_limit can be set to limit the
number of character printed in various string values. Setting it to 0
means no limit.
+=head2 Memory footprint debugging
+
+When perl is compiled with support for memory footprint debugging
+(default with Perl's malloc()), Devel::Peek provides an access to this API.
+
+Use mstat() function to emit a memory state statistic to the terminal.
+For more information on the format of output of mstat() see
+L<perldebug/Using C<$ENV{PERL_DEBUG_MSTATS}>>.
+
+Three additional functions allow access to this statistic from Perl.
+First, use C<mstats_fillhash(%hash)> to get the information contained
+in the output of mstat() into %hash. The field of this hash are
+
+ minbucket nbuckets sbrk_good sbrk_slack sbrked_remains sbrks start_slack
+ topbucket topbucket_ev topbucket_odd total total_chain total_sbrk totfree
+
+Two additional fields C<free>, C<used> contain array references which
+provide per-bucket count of free and used chunks. Two other fields
+C<mem_size>, C<available_size> contain array references which provide
+the information about the allocated size and usable size of chunks in
+each bucket. Again, see L<perldebug/Using C<$ENV{PERL_DEBUG_MSTATS}>>
+for details.
+
+Keep in mind that only the first several "odd-numbered" buckets are
+used, so the information on size of the "odd-numbered" buckets which are
+not used is probably meaningless.
+
+The information in
+
+ mem_size available_size minbucket nbuckets
+
+is the property of a particular build of perl, and does not depend on
+the current process. If you do not provide the optional argument to
+the functions mstats_fillhash(), fill_mstats(), mstats2hash(), then
+the information in fields C<mem_size>, C<available_size> is not
+updated.
+
+C<fill_mstats($buf)> is a much cheaper call (both speedwise and
+memory-wise) which collects the statistic into $buf in
+machine-readable form. At a later moment you may need to call
+C<mstats2hash($buf, %hash)> to use this information to fill %hash.
+
+All three APIs C<fill_mstats($buf)>, C<mstats_fillhash(%hash)>, and
+C<mstats2hash($buf, %hash)> are designed to allocate no memory if used
+I<the second time> on the same $buf and/or %hash.
+
+So, if you want to collect memory info in a cycle, you may call
+
+ $#buf = 999;
+ fill_mstats($_) for @buf;
+ mstats_fillhash(%report, 1); # Static info too
+
+ foreach (@buf) {
+ # Do something...
+ fill_mstats $_; # Collect statistic
+ }
+ foreach (@buf) {
+ mstats2hash($_, %report); # Preserve static info
+ # Do something with %report
+ }
+
=head1 EXAMPLES
The following examples don't attempt to show everything as that would be a
Let's begin by looking a simple scalar which is holding a string.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = "hello";
Dump $a;
If the scalar contains a number the raw SV will be leaner.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = 42;
Dump $a;
If the scalar from the previous example had an extra reference:
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = 42;
$b = \$a;
Dump $a;
This shows what a reference looks like when it references a simple scalar.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = 42;
$b = \$a;
Dump $b;
This shows what a reference to an array looks like.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = [42];
Dump $a;
The following shows the raw form of a reference to a hash.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = {hello=>42};
Dump $a;
toplevel array or hash. This number can be increased by supplying a
second argument to the function.
- use Devel::Peek 'Dump';
+ use Devel::Peek;
$a = [10,11,12,13,14];
Dump $a;
XSUB = 0x0
XSUBANY = 0
GVGV::GV = 0x1d44e8 "MY" :: "top_targets"
- FILEGV = 0x1fab74 "_<(eval 5)"
+ FILE = "(eval 5)"
DEPTH = 0
PADLIST = 0x1c9338
=over
-=item
+=item *
the subroutine is not an XSUB (since C<START> and C<ROOT> are
non-zero, and C<XSUB> is zero);
-=item
+=item *
that it was compiled in the package C<main>;
-=item
+=item *
under the name C<MY::top_targets>;
-=item
+=item *
inside a 5th eval in the program;
-=item
+=item *
it is not currently executed (see C<DEPTH>);
-=item
+=item *
it has no prototype (C<PROTOTYPE> field is missing).
-=over
+=back
=head1 EXPORTS
C<Dump>, C<mstat>, C<DeadCode>, C<DumpArray>, C<DumpWithOP> and
-C<DumpProg> by default. Additionally available C<SvREFCNT>,
-C<SvREFCNT_inc> and C<SvREFCNT_dec>.
+C<DumpProg>, C<fill_mstats>, C<mstats_fillhash>, C<mstats2hash> by
+default. Additionally available C<SvREFCNT>, C<SvREFCNT_inc> and
+C<SvREFCNT_dec>.
=head1 BUGS
projects / p5sagit/p5-mst-13.2.git / blobdiff