Cari di Perl 
     Perl User Manual
Daftar Isi ☛
(Sebelumnya) A listing of experimental feat ...Namespace for Perl's core ... (Berikutnya)
Language Reference

Perl's support for DTrace

Daftar Isi

NAME

perldtrace - Perl's support for DTrace

SYNOPSIS

  1.  # dtrace -Zn 'perl::sub-entry, perl::sub-return { trace(copyinstr(arg0)) }'
    2.  
  2.  dtrace: description 'perl::sub-entry, perl::sub-return ' matched 10 probes
    3.  
  3.  
  4.  # perl -E 'sub outer { inner(@_) } sub inner { say shift } outer("hello")'
    5.  
  5.  hello
    6.  
  6.  
  7.  (dtrace output)
    8.  
  8.  CPU ID FUNCTION:NAME
    9.  
  9.   0  75915   Perl_pp_entersub:sub-entry   BEGIN
    10.  
  10.   0  75915   Perl_pp_entersub:sub-entry   import
    11.  
  11.   0  75922  Perl_pp_leavesub:sub-return   import
    12.  
  12.   0  75922  Perl_pp_leavesub:sub-return   BEGIN
    13.  
  13.   0  75915   Perl_pp_entersub:sub-entry   outer
    14.  
  14.   0  75915   Perl_pp_entersub:sub-entry   inner
    15.  
  15.   0  75922  Perl_pp_leavesub:sub-return   inner
    16.  
  16.   0  75922  Perl_pp_leavesub:sub-return   outer
    17.

DESCRIPTION

DTrace is a framework for comprehensive system- and application-leveltracing. Perl is a DTrace provider, meaning it exposes severalprobes for instrumentation. You can use these in conjunctionwith kernel-level probes, as well as probes from other providerssuch as MySQL, in order to diagnose software defects, or even justyour application's bottlenecks.

Perl must be compiled with the -Dusedtrace option in order tomake use of the provided probes. While DTrace aims to have nooverhead when its instrumentation is not active, Perl's supportitself cannot uphold that guarantee, so it is built without DTraceprobes under most systems. One notable exception is that Mac OS Xships a /usr/bin/perl with DTrace support enabled.

HISTORY

5.
10.1

Perl's initial DTrace support was added, providing sub-entry andsub-return probes.

5.
14.0

The sub-entry and sub-return probes gain a fourth argument: thepackage name of the function.

5.
16.0

The phase-change probe was added.

PROBES

  • sub-entry(SUBNAME, FILE, LINE, PACKAGE)

    Traces the entry of any subroutine. Note that all of the variablesrefer to the subroutine that is being invoked; there is currentlyno way to get ahold of any information about the subroutine'scaller from a DTrace action.

    1.  :*perl*::sub-entry {
      2.  
    2.  printf("%s::%s entered at %s line %d\n",
      3.  
    3.    copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
      4.  
    4.  }
      5.
  • sub-return(SUBNAME, FILE, LINE, PACKAGE)

    Traces the exit of any subroutine. Note that all of the variablesrefer to the subroutine that is returning; there is currently noway to get ahold of any information about the subroutine's callerfrom a DTrace action.

    1.  :*perl*::sub-return {
      2.  
    2.  printf("%s::%s returned at %s line %d\n",
      3.  
    3.    copyinstr(arg3), copyinstr(arg0), copyinstr(arg1), arg0);
      4.  
    4.  }
      5.
  • phase-change(NEWPHASE, OLDPHASE)

    Traces changes to Perl's interpreter state. You can internalize thisas tracing changes to Perl's ${^GLOBAL_PHASE} variable, especiallysince the values for NEWPHASE and OLDPHASE are the strings that${^GLOBAL_PHASE} reports.

    1.  :*perl*::phase-change {
      2.  
    2.  printf("Phase changed from %s to %s\n",
      3.  
    3.  copyinstr(arg1), copyinstr(arg0));
      4.  
    4.  }
      5.

EXAMPLES

  • Most frequently called functions
    1.  # dtrace -qZn 'sub-entry { @[strjoin(strjoin(copyinstr(arg3),"::"),copyinstr(arg0))] = count() } END {trunc(@, 10)}'
      2.  
    2.  
    3.  Class::MOP::Attribute::slots 400
      4.  
    4.  Try::Tiny::catch 411
      5.  
    5.  Try::Tiny::try  411
      6.  
    6.  Class::MOP::Instance::inline_slot_access 451
      7.  
    7.  Class::MOP::Class::Immutable::Trait:::around 472
      8.  
    8.  Class::MOP::Mixin::AttributeCore::has_initializer   496
      9.  
    9.  Class::MOP::Method::Wrapped::__ANON__   544
      10.  
    10.  Class::MOP::Package::_package_stash 737
      11.  
    11.  Class::MOP::Class::initialize  1128
      12.  
    12.  Class::MOP::get_metaclass_by_name  1204
      13.
  • Trace function calls
    1.  # dtrace -qFZn 'sub-entry, sub-return { trace(copyinstr(arg0)) }'
      2.  
    2.  
    3.  0  -> Perl_pp_entersub BEGIN
      4.  
    4.  0  <- Perl_pp_leavesub BEGIN
      5.  
    5.  0  -> Perl_pp_entersub BEGIN
      6.  
    6.  0 -> Perl_pp_entersub  import
      7.  
    7.  0 <- Perl_pp_leavesub  import
      8.  
    8.  0  <- Perl_pp_leavesub BEGIN
      9.  
    9.  0  -> Perl_pp_entersub BEGIN
      10.  
    10.  0 -> Perl_pp_entersub  dress
      11.  
    11.  0 <- Perl_pp_leavesub  dress
      12.  
    12.  0 -> Perl_pp_entersub  dirty
      13.  
    13.  0 <- Perl_pp_leavesub  dirty
      14.  
    14.  0 -> Perl_pp_entersub  whiten
      15.  
    15.  0 <- Perl_pp_leavesub  whiten
      16.  
    16.  0  <- Perl_dounwind   BEGIN
      17.
  • Function calls during interpreter cleanup
    1.  # dtrace -Zn 'phase-change /copyinstr(arg0) == "END"/ { self->ending = 1 } sub-entry /self->ending/ { trace(copyinstr(arg0)) }'
      2.  
    2.  
    3.  CPU ID FUNCTION:NAME
      4.  
    4.   1  77214   Perl_pp_entersub:sub-entry   END
      5.  
    5.   1  77214   Perl_pp_entersub:sub-entry   END
      6.  
    6.   1  77214   Perl_pp_entersub:sub-entry   cleanup
      7.  
    7.   1  77214   Perl_pp_entersub:sub-entry   _force_writable
      8.  
    8.   1  77214   Perl_pp_entersub:sub-entry   _force_writable
      9.
  • System calls at compile time
    1.  # 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) }'
      2.  
    2.  
    3.  lseek   310
      4.  
    4.  read 374
      5.  
    5.  stat64 1056
      6.

REFERENCES

AUTHORS

Shawn M Moore sartak@gmail.com

Page index
 
Source : perldoc.perl.org - Official documentation for the Perl programming language
Site maintained by Jon Allen (JJ)     See the project page for more details
Documentation maintained by the Perl 5 Porters
(Sebelumnya) A listing of experimental feat ...Namespace for Perl's core ... (Berikutnya)