perl5.git.perl.org Git - perl5.git/blame_incremental

... / ...

Commit	Line	Data
	1	=head1 NAME
	2
	3	perldtrace - Perl's support for DTrace
	4
	5	=head1 SYNOPSIS
	6
	7	# dtrace -Zn 'perl::sub-entry, perl::sub-return { trace(copyinstr(arg0)) }'
	8	dtrace: description 'perl::sub-entry, perl::sub-return ' matched 10 probes
	9
	10	# perl -E 'sub outer { inner(@_) } sub inner { say shift } outer("hello")'
	11	hello
	12
	13	(dtrace output)
	14	CPU ID FUNCTION:NAME
	15	0 75915 Perl_pp_entersub:sub-entry BEGIN
	16	0 75915 Perl_pp_entersub:sub-entry import
	17	0 75922 Perl_pp_leavesub:sub-return import
	18	0 75922 Perl_pp_leavesub:sub-return BEGIN
	19	0 75915 Perl_pp_entersub:sub-entry outer
	20	0 75915 Perl_pp_entersub:sub-entry inner
	21	0 75922 Perl_pp_leavesub:sub-return inner
	22	0 75922 Perl_pp_leavesub:sub-return outer
	23
	24	=head1 DESCRIPTION
	25
	26	DTrace is a framework for comprehensive system- and application-level
	27	tracing. Perl is a DTrace I<provider>, meaning it exposes several
	28	I<probes> for instrumentation. You can use these in conjunction
	29	with kernel-level probes, as well as probes from other providers
	30	such as MySQL, in order to diagnose software defects, or even just
	31	your application's bottlenecks.
	32
	33	Perl must be compiled with the C<-Dusedtrace> option in order to
	34	make use of the provided probes. While DTrace aims to have no
	35	overhead when its instrumentation is not active, Perl's support
	36	itself cannot uphold that guarantee, so it is built without DTrace
	37	probes under most systems. One notable exception is that Mac OS X
	38	ships a F</usr/bin/perl> with DTrace support enabled.
	39
	40	=head1 HISTORY
	41
	42	=over 4
	43
	44	=item 5.10.1
	45
	46	Perl's initial DTrace support was added, providing C<sub-entry> and
	47	C<sub-return> probes.
	48
	49	=item 5.14.0
	50
	51	The C<sub-entry> and C<sub-return> probes gain a fourth argument: the
	52	package name of the function.
	53
	54	=back
	55
	56	=head1 PROBES
	57
	58	=over 4
	59
	60	=item sub-entry(SUBNAME, FILE, LINE, PACKAGE)
	61
	62	Traces the entry of any subroutine. Note that all of the variables
	63	refer to the subroutine that is being invoked; there is currently
	64	no way to get ahold of any information about the subroutine's
	65	I<caller> from a DTrace action.
	66
	67	:perl::sub-entry {
	68	printf("%s::%s entered at %s line %d\n",
	69	copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
	70	}
	71
	72	=item sub-return(SUBNAME, FILE, LINE, PACKAGE)
	73
	74	Traces the exit of any subroutine. Note that all of the variables
	75	refer to the subroutine that is returning; there is currently no
	76	way to get ahold of any information about the subroutine's I<caller>
	77	from a DTrace action.
	78
	79	:perl::sub-return {
	80	printf("%s::%s returned at %s line %d\n",
	81	copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
	82	}
	83
	84	=back
	85
	86	=head1 EXAMPLES
	87
	88	=over 4
	89
	90	=item Most frequently called functions
	91
	92	# dtrace -qZn 'sub-entry { @[strjoin(strjoin(copyinstr(arg3),"::"),copyinstr(arg0))] = count() } END {trunc(@, 10)}'
	93
	94	Class::MOP::Attribute::slots 400
	95	Try::Tiny::catch 411
	96	Try::Tiny::try 411
	97	Class::MOP::Instance::inline_slot_access 451
	98	Class::MOP::Class::Immutable::Trait:::around 472
	99	Class::MOP::Mixin::AttributeCore::has_initializer 496
	100	Class::MOP::Method::Wrapped::__ANON__ 544
	101	Class::MOP::Package::_package_stash 737
	102	Class::MOP::Class::initialize 1128
	103	Class::MOP::get_metaclass_by_name 1204
	104
	105	=item Trace function calls
	106
	107	# dtrace -qFZn 'sub-entry, sub-return { trace(copyinstr(arg0)) }'
	108
	109	0 -> Perl_pp_entersub BEGIN
	110	0 <- Perl_pp_leavesub BEGIN
	111	0 -> Perl_pp_entersub BEGIN
	112	0 -> Perl_pp_entersub import
	113	0 <- Perl_pp_leavesub import
	114	0 <- Perl_pp_leavesub BEGIN
	115	0 -> Perl_pp_entersub BEGIN
	116	0 -> Perl_pp_entersub dress
	117	0 <- Perl_pp_leavesub dress
	118	0 -> Perl_pp_entersub dirty
	119	0 <- Perl_pp_leavesub dirty
	120	0 -> Perl_pp_entersub whiten
	121	0 <- Perl_pp_leavesub whiten
	122	0 <- Perl_dounwind BEGIN
	123
	124	=back
	125
	126	=head1 REFERENCES
	127
	128	=over 4
	129
	130	=item DTrace User Guide
	131
	132	L<http://download.oracle.com/docs/cd/E19082-01/819-3620/index.html>
	133
	134	=item DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD
	135
	136	L<http://www.amazon.com/DTrace-Dynamic-Tracing-Solaris-FreeBSD/dp/0132091518/>
	137
	138	=back
	139
	140	=head1 AUTHORS
	141
	142	Shawn M Moore C<sartak@gmail.com>
	143
	144	=cut