summaryrefslogtreecommitdiff
path: root/Master/tlpkg/tlperl/lib/pods/perldtrace.pod
diff options
context:
space:
mode:
Diffstat (limited to 'Master/tlpkg/tlperl/lib/pods/perldtrace.pod')
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldtrace.pod179
1 files changed, 179 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/pods/perldtrace.pod b/Master/tlpkg/tlperl/lib/pods/perldtrace.pod
new file mode 100644
index 00000000000..39551e17490
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldtrace.pod
@@ -0,0 +1,179 @@
+=head1 NAME
+
+perldtrace - Perl's support for DTrace
+
+=head1 SYNOPSIS
+
+ # dtrace -Zn 'perl::sub-entry, perl::sub-return { trace(copyinstr(arg0)) }'
+ dtrace: description 'perl::sub-entry, perl::sub-return ' matched 10 probes
+
+ # perl -E 'sub outer { inner(@_) } sub inner { say shift } outer("hello")'
+ hello
+
+ (dtrace output)
+ CPU ID FUNCTION:NAME
+ 0 75915 Perl_pp_entersub:sub-entry BEGIN
+ 0 75915 Perl_pp_entersub:sub-entry import
+ 0 75922 Perl_pp_leavesub:sub-return import
+ 0 75922 Perl_pp_leavesub:sub-return BEGIN
+ 0 75915 Perl_pp_entersub:sub-entry outer
+ 0 75915 Perl_pp_entersub:sub-entry inner
+ 0 75922 Perl_pp_leavesub:sub-return inner
+ 0 75922 Perl_pp_leavesub:sub-return outer
+
+=head1 DESCRIPTION
+
+DTrace is a framework for comprehensive system- and application-level
+tracing. Perl is a DTrace I<provider>, meaning it exposes several
+I<probes> for instrumentation. You can use these in conjunction
+with kernel-level probes, as well as probes from other providers
+such as MySQL, in order to diagnose software defects, or even just
+your application's bottlenecks.
+
+Perl must be compiled with the C<-Dusedtrace> option in order to
+make use of the provided probes. While DTrace aims to have no
+overhead when its instrumentation is not active, Perl's support
+itself cannot uphold that guarantee, so it is built without DTrace
+probes under most systems. One notable exception is that Mac OS X
+ships a F</usr/bin/perl> with DTrace support enabled.
+
+=head1 HISTORY
+
+=over 4
+
+=item 5.10.1
+
+Perl's initial DTrace support was added, providing C<sub-entry> and
+C<sub-return> probes.
+
+=item 5.14.0
+
+The C<sub-entry> and C<sub-return> probes gain a fourth argument: the
+package name of the function.
+
+=item 5.16.0
+
+The C<phase-change> probe was added.
+
+=back
+
+=head1 PROBES
+
+=over 4
+
+=item sub-entry(SUBNAME, FILE, LINE, PACKAGE)
+
+Traces the entry of any subroutine. Note that all of the variables
+refer to the subroutine that is being invoked; there is currently
+no way to get ahold of any information about the subroutine's
+I<caller> from a DTrace action.
+
+ :*perl*::sub-entry {
+ printf("%s::%s entered at %s line %d\n",
+ copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
+ }
+
+=item sub-return(SUBNAME, FILE, LINE, PACKAGE)
+
+Traces the exit of any subroutine. Note that all of the variables
+refer to the subroutine that is returning; there is currently no
+way to get ahold of any information about the subroutine's I<caller>
+from a DTrace action.
+
+ :*perl*::sub-return {
+ printf("%s::%s returned at %s line %d\n",
+ copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
+ }
+
+=item phase-change(NEWPHASE, OLDPHASE)
+
+Traces changes to Perl's interpreter state. You can internalize this
+as tracing changes to Perl's C<${^GLOBAL_PHASE}> variable, especially
+since the values for C<NEWPHASE> and C<OLDPHASE> are the strings that
+C<${^GLOBAL_PHASE}> reports.
+
+ :*perl*::phase-change {
+ printf("Phase changed from %s to %s\n",
+ copyinstr(arg1), copyinstr(arg0));
+ }
+
+=back
+
+=head1 EXAMPLES
+
+=over 4
+
+=item Most frequently called functions
+
+ # dtrace -qZn 'sub-entry { @[strjoin(strjoin(copyinstr(arg3),"::"),copyinstr(arg0))] = count() } END {trunc(@, 10)}'
+
+ Class::MOP::Attribute::slots 400
+ Try::Tiny::catch 411
+ Try::Tiny::try 411
+ Class::MOP::Instance::inline_slot_access 451
+ Class::MOP::Class::Immutable::Trait:::around 472
+ Class::MOP::Mixin::AttributeCore::has_initializer 496
+ Class::MOP::Method::Wrapped::__ANON__ 544
+ Class::MOP::Package::_package_stash 737
+ Class::MOP::Class::initialize 1128
+ Class::MOP::get_metaclass_by_name 1204
+
+=item Trace function calls
+
+ # dtrace -qFZn 'sub-entry, sub-return { trace(copyinstr(arg0)) }'
+
+ 0 -> Perl_pp_entersub BEGIN
+ 0 <- Perl_pp_leavesub BEGIN
+ 0 -> Perl_pp_entersub BEGIN
+ 0 -> Perl_pp_entersub import
+ 0 <- Perl_pp_leavesub import
+ 0 <- Perl_pp_leavesub BEGIN
+ 0 -> Perl_pp_entersub BEGIN
+ 0 -> Perl_pp_entersub dress
+ 0 <- Perl_pp_leavesub dress
+ 0 -> Perl_pp_entersub dirty
+ 0 <- Perl_pp_leavesub dirty
+ 0 -> Perl_pp_entersub whiten
+ 0 <- Perl_pp_leavesub whiten
+ 0 <- Perl_dounwind BEGIN
+
+=item Function calls during interpreter cleanup
+
+ # dtrace -Zn 'phase-change /copyinstr(arg0) == "END"/ { self->ending = 1 } sub-entry /self->ending/ { trace(copyinstr(arg0)) }'
+
+ CPU ID FUNCTION:NAME
+ 1 77214 Perl_pp_entersub:sub-entry END
+ 1 77214 Perl_pp_entersub:sub-entry END
+ 1 77214 Perl_pp_entersub:sub-entry cleanup
+ 1 77214 Perl_pp_entersub:sub-entry _force_writable
+ 1 77214 Perl_pp_entersub:sub-entry _force_writable
+
+=item System calls at compile time
+
+ # 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) }'
+
+ lseek 310
+ read 374
+ stat64 1056
+
+=back
+
+=head1 REFERENCES
+
+=over 4
+
+=item DTrace User Guide
+
+L<http://download.oracle.com/docs/cd/E19082-01/819-3620/index.html>
+
+=item DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD
+
+L<http://www.amazon.com/DTrace-Dynamic-Tracing-Solaris-FreeBSD/dp/0132091518/>
+
+=back
+
+=head1 AUTHORS
+
+Shawn M Moore C<sartak@gmail.com>
+
+=cut