comment on

This all started with a report from a user about Class::Accessor::Grouped being much slower on 5.10 compared to 5.8.8.

At this point, I call 'not it'...but only because I really don't know what in the hell is going on. Two brand new fresh FreeBSD 6.2 installs. One with a a compiled (not ports) Perl 5.8.8 and the other with a compiled 5.10.0.

The test case is simple set_inherited, sans C::A::G in the picture, since the reporter noted set was slower as well (which BTW has no MRO interaction):

#test.pl
use lib '.';
use Foo;
use Benchmark ':all';
 
my $f = bless {}, 'Foo';
 
timethese(0, {
    set_inherited_class  => sub {Foo->set_inherited('bar', 'baz')},
    set_inherited_object => sub {$f->set_inherited('bar', 'baz')}
});

##Foo.pm
package Foo;
use Scalar::Util qw/blessed reftype/;

sub set_inherited {
    my ($self, $set, $val) = @_;

    if (blessed $self) {
        if (reftype $self eq 'HASH') {
            return $self->{$set} = $val;
        } else {
            croak('Cannot set inherited value on an object instance th
+at is not hash-based');
        };
    } else {
        no strict 'refs';

        return ${$self.'::__cag_'.$set} = $val;
    };
}

1;
[download]

The results are:

Perl 5.8.8 Machine:
> Benchmark: running set_inherited_class, set_inherited_object for at 
+least 3 CPU seconds...
> set_inherited_class:  4 wallclock secs ( 3.16 usr +  0.00 sys =  3.1
+6 CPU) @ 575596.40/s (n=1821223)
> set_inherited_object:  3 wallclock secs ( 3.16 usr + -0.01 sys =  3.
+15 CPU) @ 687794.82/s (n=2165479)
> claco@fbsd588 ~ $ 

Perl 5.10.0 Machine:
> Benchmark: running set_inherited_class, set_inherited_object for at 
+least 3 CPU seconds...
> set_inherited_class:  3 wallclock secs ( 3.12 usr +  0.01 sys =  3.1
+3 CPU) @ 335388.09/s (n=1050708)
> set_inherited_object:  2 wallclock secs ( 3.15 usr +  0.00 sys =  3.
+15 CPU) @ 412676.76/s (n=1299287)
> claco@fbsd510 ~ $
[download]

My to my shock, if I whittle down the code in set_inherited to just this:

package Foo;
use Scalar::Util qw/blessed reftype/;

sub set_inherited {
    my ($self, $set, $val) = @_;

}

1;
[download]

performance still seriouesly sucks:

5.8.8
> Benchmark: running set_inherited_class, set_inherited_object for at 
+least 3 CPU seconds...
> set_inherited_class:  3 wallclock secs ( 3.08 usr +  0.02 sys =  3.0
+9 CPU) @ 1199923.07/s (n=3712262)
> set_inherited_object:  4 wallclock secs ( 3.27 usr +  0.00 sys =  3.
+27 CPU) @ 1380589.06/s (n=4519272)
> claco@fbsd588 ~ $ 

5.10.0
> Benchmark: running set_inherited_class, set_inherited_object for at 
+least 3 CPU seconds...
> set_inherited_class:  4 wallclock secs ( 3.09 usr +  0.01 sys =  3.1
+0 CPU) @ 536733.34/s (n=1664712)
> set_inherited_object:  4 wallclock secs ( 3.13 usr +  0.00 sys =  3.
+13 CPU) @ 638055.42/s (n=1998908)
> claco@fbsd510 ~ $
[download]

A this point, I'm stumped. my ($, $, $) = @_; is a common idiom. Changing to this makes 5.10 faster.

package Foo;
use Scalar::Util qw/blessed reftype/;

sub set_inherited {
    my $self = shift;
    my $set = shift;
    my $val = shift;

}

1;
[download]

I know shift is always faster than assigning @_, but the performaance difference of assigning @_ on 5.10 vs. 5.8.8 is worrysome to me.

Updated with -V output

Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
  Platform:
    osname=freebsd, osvers=6.2-release, archname=i386-freebsd
    uname='freebsd fbsd588.local 6.2-release freebsd 6.2-release #0: f
+ri jan 12 10:40:27 utc 2007 root@dessler.cse.buffalo.edu:usrobjusrsrc
+sysgeneric i386 '
    config_args='-de'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultipl
+icity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-stri
+ct-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include'
+,
    optimize='-O',
    cppflags='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-strict-aliasi
+ng -pipe -Wdeclaration-after-statement -I/usr/local/include'
    ccversion='', gccversion='3.4.6 [FreeBSD] 20060305', gccosandvers=
+''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
+ lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags ='-Wl,-E  -L/usr/local/lib'
    libpth=/usr/lib /usr/local/lib
    libs=-lm -lcrypt -lutil -lc
    perllibs=-lm -lcrypt -lutil -lc
    libc=, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-DPIC -fPIC', lddlflags='-shared  -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: PERL_MALLOC_WRAP USE_LARGE_FILES USE_PERLIO
  Built under freebsd
  Compiled at Dec 22 2007 15:52:43
  @INC:
    /usr/local/lib/perl5/5.8.8/i386-freebsd
    /usr/local/lib/perl5/5.8.8
    /usr/local/lib/perl5/site_perl/5.8.8/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.8.8
    /usr/local/lib/perl5/site_perl
    .

-------------

Summary of my perl5 (revision 5 version 10 subversion 0) configuration
+:
  Platform:
    osname=freebsd, osvers=6.2-release, archname=i386-freebsd
    uname='freebsd fbsd510.local 6.2-release freebsd 6.2-release #0: f
+ri jan 12 10:40:27 utc 2007 root@dessler.cse.buffalo.edu:usrobjusrsrc
+sysgeneric i386 '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=und
+ef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-stri
+ct-aliasing -pipe -I/usr/local/include',
    optimize='-O',
    cppflags='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-strict-aliasi
+ng -pipe -I/usr/local/include'
    ccversion='', gccversion='3.4.6 [FreeBSD] 20060305', gccosandvers=
+''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
+ lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags ='-Wl,-E  -L/usr/local/lib'
    libpth=/usr/lib /usr/local/lib
    libs=-lm -lcrypt -lutil -lc
    perllibs=-lm -lcrypt -lutil -lc
    libc=, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-DPIC -fPIC', lddlflags='-shared  -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: PERL_DONT_CREATE_GVSV PERL_MALLOC_WRAP
                        USE_LARGE_FILES USE_PERLIO
  Built under freebsd
  Compiled at Dec 22 2007 17:32:47
  @INC:
    /usr/local/lib/perl5/5.10.0/i386-freebsd
    /usr/local/lib/perl5/5.10.0
    /usr/local/lib/perl5/site_perl/5.10.0/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.10.0
    .
[download]

Updated: Also this from a thread on use.perl. I hate cross posting, but given the nature of this issue...

In reply to 5:10: Why is this slower than 5.8.8? by jk2addict

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