NAME
Devel::DProf - a Perl code profiler
SYNOPSIS
perl5 -d:DProf test.plDESCRIPTION
The Devel::DProf package is a Perl code profiler. This will collect information on the execution time of a Perl script and of the subs in that script. This information can be used to determine which subroutines are using the most time and which subroutines are being called most often. This information can also be used to create an execution graph of the script, showing subroutine relationships.
To profile a Perl script run the perl interpreter with the -d debugging switch. The profiler uses the debugging hooks. So to profile script test.pl the following command should be used:
perl5 -d:DProf test.plWhen the script terminates the profiler will dump the profile information to a file called tmon.out. A tool like dprofpp can be used to interpret the information which is in that profile. The following command will print the top 15 subroutines which used the most time:
dprofppTo print an execution graph of the subroutines in the script use the following command:
dprofpp -TConsult dprofpp for other options.
PROFILE FORMAT
The profile is a text file which looks like this:
#fOrTyTwO
$hz=100;
$XS_VERSION='DProf 19970606';
# All values are given in HZ
$rrun_utime=2; $rrun_stime=0; $rrun_rtime=7
PART2
+ 26 28 566822884 DynaLoader::import
- 26 28 566822884 DynaLoader::import
+ 27 28 566822885 main::bar
- 27 28 566822886 main::bar
+ 27 28 566822886 main::baz
+ 27 28 566822887 main::bar
- 27 28 566822888 main::bar
[....]The first line is the magic number. The second line is the hertz value, or clock ticks, of the machine where the profile was collected. The third line is the name and version identifier of the tool which created the profile. The fourth line is a comment. The fifth line contains three variables holding the user time, system time, and realtime of the process while it was being profiled. The sixth line indicates the beginning of the sub entry/exit profile section.
The columns in PART2 are:
sub entry(+)/exit(-) mark
app's user time at sub entry/exit mark, in ticks
app's system time at sub entry/exit mark, in ticks
app's realtime at sub entry/exit mark, in ticks
fully-qualified sub name, when possibleAUTOLOAD
When Devel::DProf finds a call to an &AUTOLOAD subroutine it looks at the $AUTOLOAD variable to find the real name of the sub being called. See "Autoloading" in perlsub.
ENVIRONMENT
PERL_DPROF_BUFFER sets size of output buffer in words. Defaults to 2**14.
PERL_DPROF_TICKS sets number of ticks per second on some systems where a replacement for times() is used. Defaults to the value of HZ macro.
BUGS
Builtin functions cannot be measured by Devel::DProf.
If the Perl is new enough (so PERLDBf_NONAME is defined), profiler may not survive assignments of strings to $DB::sub. Such assignments were useful with older versions of Perl near `goto &subr'. They are not needed any more.
One such assignment is in Tk::Widget::AUTOLOAD as of 402.003.
Mail bug reports and feature requests to the perl5-porters mailing list at <perl5-porters@africa.nicoh.com>.