Re: Strange performance problem inside POE

I found out the reason for the bad performance. It was due to the 
use:age of Switch. It seems the Switch module has a severe impact on 
regexp matching in genenaral and on /\G.../gc constructs in particular, 
sometimes more than 30 times slower. Must be something with the source 
filters use by Switch.

As soon as I removed use Switch and reconstructed my switch statement my 
program became about 50 times faster!

NB: this had nothing to do with POE at all. It can also be me using an 
old perl release 5.8.X.

Attached is an interlaced SmallProf listing between the two cases.
Switch maintainer is notified. Thanks to you people who came up with 
ideas how to solve my problem.

FAST:         0   0.00000   0.00000    24:sub dict {
SLOW:         0   0.00000   0.00000    24:sub dict {
FAST:       853   0.00037   0.01000    25:    ${$_[0]} =~ /\G\{/gc;
SLOW:       853   0.36373   0.36000    25:    ${$_[0]} =~ /\G\{/gc;
FAST:       853   0.00162   0.03000    26:    my $h = {};
SLOW:       853   0.00240   0.02000    26:    my $h = {};
FAST:       853   0.00501   0.03000    27:    while (${$_[0]} =~
SLOW:       853   0.35299   0.47000    27:    while (${$_[0]} =~
FAST:     10053   0.01812   0.20000    28: my $key = $1;
SLOW:     10053   0.04336   0.23000    28: my $key = $1;
FAST:     10053   0.01980   0.20000    29: if (${$_[0]} =~ /\G(?=\{)/gc) {
SLOW:     10053   4.28763   4.32000    29: if (${$_[0]} =~ /\G(?=\{)/gc) {
FAST:         0   0.00000   0.00000    30:     $h->{$key} = dict($_[0]);
SLOW:         0   0.00000   0.00000    30:     $h->{$key} = dict($_[0]);
FAST:         0   0.00000   0.00000    32: } elsif (${$_[0]} =~ 
/\G([^\|\}]*)/gc) {
SLOW:         0   0.00000   0.00000    32: } elsif (${$_[0]} =~ 
/\G([^\|\}]*)/gc) {
FAST:      9201   0.01001   0.14000    33:     my $value = $1;
SLOW:      9201   0.02721   0.16000    33:     my $value = $1;
FAST:      9201   0.02044   0.17000    34:     $h->{$key} = $value;
SLOW:      9201   0.02051   0.17000    34:     $h->{$key} = $value;
FAST:         0   0.00000   0.00000    36: }
SLOW:         0   0.00000   0.00000    36: }
FAST:     10053   0.01922   0.12000    37: return $h if ${$_[0]} =~ 
/\G\}/gc;
SLOW:     10053   0.38550   0.48000    37: return $h if ${$_[0]} =~ 
/\G\}/gc;
FAST:      9200   0.05767   0.22000    38: ${$_[0]} =~ /\G\|/gc;
SLOW:      9200   7.62619   7.54000    38: ${$_[0]} =~ /\G\|/gc;
FAST:         0   0.00000   0.00000    39:    }
SLOW:         0   0.00000   0.00000    39:    }
FAST:         0   0.00000   0.00000    40:}
FAST:         0   0.00000   0.00000    40:}



Jan Sundberg skrev:
> Hello.
>
> I'm writing a regexp based parser based on the perlop manpage 
> /\G.../gc example:
>
>
>
>