p5pRT
commented
15 years ago From alex.davies@talktalk.net
Created by alex@Amelie
This is on Win32...
I noticed a slowdown in performance of C\< /pat/i > case insensitive regular expressions when used in fork code. Interestingly if the regexp was compiled within the fork'd code it ran at the expected rate. NB. the same results were obtained in either case - it was just the time taken that was different.
The following testcase shows an interesting difference in behaviour which i suspect is the culprit of the difference in time taken:
# %\<
use re qw(Debug All);
my $pid = fork; defined $pid or die;
if ($pid == 0) { $_ = "abcNEEDLE123\n";
print STDERR "\n## 1 ##\n\n"; /needle/i;
print STDERR "\n## 2 ##\n\n"; eval q{ /needle/i };
exit; }
while (wait() != -1) {}
$_ = "abcNEEDLE123\n";
print STDERR "\n## 3 ##\n\n"; /needle/i;
# >%
And here is the output:
# %\<
Compiling REx "needle"
Final program:
1: EXACTF \
## 1 ##
Matching REx "needle" against "abcNEEDLE123%n"
0 \<> \
## 2 ##
Compiling REx "needle"
Final program:
1: EXACTF \
## 3 ##
Matching REx "needle" against "abcNEEDLE123%n"
Matching stclass EXACTF \
# >%
So it appears the /regexp/i is 'run' differently within the child thread if it was compiled in the main thread.
Additionally\, running the testcase on my Strawberry 5.10 perl also gave some assert warnings:
Assertion ((svtype)((_svi)->sv_flags & 0xff)) >= SVt_PV failed: file "re_exec.c"\, line 2561
Is this a bug\, or simply a necesary change in the code path taken to get /regexp/i to work in a threaded environment?
Thanks for taking a look.
Cheers\, alex.
khwilliamson
Migrated from rt.perl.org#63284 (status was 'open')
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