1PERLDTRACE(1) Perl Programmers Reference Guide PERLDTRACE(1)
2
6 perldtrace - Perl's support for DTrace
7
9 # dtrace -Zn 'perl::sub-entry, perl::sub-return { trace(copyinstr(arg0)) }'
10 dtrace: description 'perl::sub-entry, perl::sub-return ' matched 10 probes
11 # perl -E 'sub outer { inner(@_) } sub inner { say shift } outer("hello")'
13 hello
14 (dtrace output)
16 CPU ID FUNCTION:NAME
17 0 75915 Perl_pp_entersub:sub-entry BEGIN
18 0 75915 Perl_pp_entersub:sub-entry import
19 0 75922 Perl_pp_leavesub:sub-return import
20 0 75922 Perl_pp_leavesub:sub-return BEGIN
21 0 75915 Perl_pp_entersub:sub-entry outer
22 0 75915 Perl_pp_entersub:sub-entry inner
23 0 75922 Perl_pp_leavesub:sub-return inner
24 0 75922 Perl_pp_leavesub:sub-return outer
25
27 DTrace is a framework for comprehensive system- and application-level
28 tracing. Perl is a DTrace provider, meaning it exposes several probes
29 for instrumentation. You can use these in conjunction with kernel-level
30 probes, as well as probes from other providers such as MySQL, in order
31 to diagnose software defects, or even just your application's
32 bottlenecks.
33 Perl must be compiled with the "-Dusedtrace" option in order to make
35 use of the provided probes. While DTrace aims to have no overhead when
36 its instrumentation is not active, Perl's support itself cannot uphold
37 that guarantee, so it is built without DTrace probes under most
38 systems. One notable exception is that Mac OS X ships a /usr/bin/perl
39 with DTrace support enabled.
40
42 5.10.1
43 Perl's initial DTrace support was added, providing "sub-entry" and
44 "sub-return" probes.
45 5.14.0
47 The "sub-entry" and "sub-return" probes gain a fourth argument: the
48 package name of the function.
49 5.16.0
51 The "phase-change" probe was added.
52
54 sub-entry(SUBNAME, FILE, LINE, PACKAGE)
55 Traces the entry of any subroutine. Note that all of the variables
56 refer to the subroutine that is being invoked; there is currently
57 no way to get ahold of any information about the subroutine's
58 caller from a DTrace action.
59 :*perl*::sub-entry {
61 printf("%s::%s entered at %s line %d\n",
62 copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
63 }
64 sub-return(SUBNAME, FILE, LINE, PACKAGE)
66 Traces the exit of any subroutine. Note that all of the variables
67 refer to the subroutine that is returning; there is currently no
68 way to get ahold of any information about the subroutine's caller
69 from a DTrace action.
70 :*perl*::sub-return {
72 printf("%s::%s returned at %s line %d\n",
73 copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
74 }
75 phase-change(NEWPHASE, OLDPHASE)
77 Traces changes to Perl's interpreter state. You can internalize
78 this as tracing changes to Perl's "${^GLOBAL_PHASE}" variable,
79 especially since the values for "NEWPHASE" and "OLDPHASE" are the
80 strings that "${^GLOBAL_PHASE}" reports.
81 :*perl*::phase-change {
83 printf("Phase changed from %s to %s\n",
84 copyinstr(arg1), copyinstr(arg0));
85 }
86
88 Most frequently called functions
89 # dtrace -qZn 'sub-entry { @[strjoin(strjoin(copyinstr(arg3),"::"),copyinstr(arg0))] = count() } END {trunc(@, 10)}'
90 Class::MOP::Attribute::slots 400
92 Try::Tiny::catch 411
93 Try::Tiny::try 411
94 Class::MOP::Instance::inline_slot_access 451
95 Class::MOP::Class::Immutable::Trait:::around 472
96 Class::MOP::Mixin::AttributeCore::has_initializer 496
97 Class::MOP::Method::Wrapped::__ANON__ 544
98 Class::MOP::Package::_package_stash 737
99 Class::MOP::Class::initialize 1128
100 Class::MOP::get_metaclass_by_name 1204
101 Trace function calls
103 # dtrace -qFZn 'sub-entry, sub-return { trace(copyinstr(arg0)) }'
104 0 -> Perl_pp_entersub BEGIN
106 0 <- Perl_pp_leavesub BEGIN
107 0 -> Perl_pp_entersub BEGIN
108 0 -> Perl_pp_entersub import
109 0 <- Perl_pp_leavesub import
110 0 <- Perl_pp_leavesub BEGIN
111 0 -> Perl_pp_entersub BEGIN
112 0 -> Perl_pp_entersub dress
113 0 <- Perl_pp_leavesub dress
114 0 -> Perl_pp_entersub dirty
115 0 <- Perl_pp_leavesub dirty
116 0 -> Perl_pp_entersub whiten
117 0 <- Perl_pp_leavesub whiten
118 0 <- Perl_dounwind BEGIN
119 Function calls during interpreter cleanup
121 # dtrace -Zn 'phase-change /copyinstr(arg0) == "END"/ { self->ending = 1 } sub-entry /self->ending/ { trace(copyinstr(arg0)) }'
122 CPU ID FUNCTION:NAME
124 1 77214 Perl_pp_entersub:sub-entry END
125 1 77214 Perl_pp_entersub:sub-entry END
126 1 77214 Perl_pp_entersub:sub-entry cleanup
127 1 77214 Perl_pp_entersub:sub-entry _force_writable
128 1 77214 Perl_pp_entersub:sub-entry _force_writable
129 System calls at compile time
131 # dtrace -qZn 'phase-change /copyinstr(arg0) == "START"/ { self->interesting = 1 } phase-change /copyinstr(arg0) == "RUN"/ { self->interesting = 0 } syscall::: /self->interesting/ { @[probefunc] = count() } END { trunc(@, 3) }'
132 lseek 310
134 read 374
135 stat64 1056
136
138 DTrace User Guide
139 http://download.oracle.com/docs/cd/E19082-01/819-3620/index.html
140 <http://download.oracle.com/docs/cd/E19082-01/819-3620/index.html>
141 DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD
143 http://www.amazon.com/DTrace-Dynamic-Tracing-Solaris-FreeBSD/dp/0132091518/
144 <http://www.amazon.com/DTrace-Dynamic-Tracing-Solaris-
145 FreeBSD/dp/0132091518/>
146
148 Shawn M Moore "sartak@gmail.com"
149perl v5.16.3 2013-03-04 PERLDTRACE(1)