1Devel::FastProf(3)    User Contributed Perl Documentation   Devel::FastProf(3)
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NAME

6       Devel::FastProf - "fast" perl per-line profiler
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SYNOPSIS

9         $ perl -d:FastProf my_script.pl
10         $ fprofpp -t 10
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ABSTRACT

13       Devel::FastProf tells you how much time has been spent on every line of
14       your program.
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DESCRIPTION

17       "Devel::FastProf" is a perl per-line profiler. What that means is that
18       it can tell you how much time is spent on every line of a perl script
19       (the standard Devel::DProf is a per-subroutine profiler).
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21       I have been the maintainer of Devel::SmallProf for some time and
22       although I found it much more useful that Devel::DProf, it had an
23       important limitation: it was terribly slow, around 50 times slower than
24       the profiled script being run out of the profiler.
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26       So, I rewrote it from scratch in C, and the result is
27       "Devel::FastProf", that runs only between 3 and 5 times slower than
28       under normal execution... well, maybe I should have called it
29       "Devel::NotSoSlowProf" ;-)
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31       To use "Devel::FastProf" with your programs, you have to call perl with
32       the "-d" switch (see perlrun) as follows:
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34         $ perl -d:FastProf my_script.pl
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36       "Devel::FastProf" will write the profiling information to a file named
37       "fastprof.out" under the current directory.
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39       To analyse the information on this file use the post processor script
40       fprofpp included with this package.
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42       Some options can be passed to "Devel::FastProf" via the environment
43       variable "FASTPROF_CONFIG":
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45       filename=otherfn.out
46           allows to change the name of the output file.
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48       usecputime
49           by default, "Devel::FastProf" meassures the wall clock time spent
50           on every line, but if this entry is included it will use the cpu
51           time (user+system) instead.
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53       canfork
54           this option has to be used if the profiled script forks new
55           processes, if you forget to do so, a corrupted "fastprof.out" file
56           could be generated.
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58           Activating this mode causes a big performance penalty because write
59           operations from all the processes have to be serialized using
60           locks. That is why it is not active by default.
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62       This is an example of how to set those options:
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64         $ FASTPROF_CONFIG="usecputime,filename=/tmp/fp.out" \
65             perl -d:FastProf myscript.pl
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BUGS

68       No Windows! No threads!
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70       Only tested on Linux. It is know not to work under Solaris.
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72       The code of subroutines defined inside "eval "..."" constructions that
73       do not include any other code will not be available on the reports.
74       This is caused by a limitation on the perl interpreter.
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76       Option -g is buggy, it only works when all the modules are loaded in
77       the original process.
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79       Perl 5.8.8 or later is recomended. Older versions have a bug that cause
80       this profiler to be slower.
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82       If you find any bug, please, send me an e-mail to sfandino@yahoo.com or
83       report it via the CPAN RT system.
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SEE ALSO

86       fprofpp, perlrun, Devel::SmallProf, Devel::Dprof, perldebug and
87       perldebguts.
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90       Copyright (C) 2005-2007 by Salvador Fandiño <sfandino@yahoo.com>.
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92       This library is free software; you can redistribute it and/or modify it
93       under the same terms as Perl itself, either Perl version 5.8.7 or, at
94       your option, any later version of Perl 5 you may have available.
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98perl v5.32.0                      2020-07-28                Devel::FastProf(3)
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