Reworked information on RH perl performance issues

[dbsrgits/DBIx-Class.git] / t / 99rh_perl_perf_bug.t

diff --git a/t/99rh_perl_perf_bug.t b/t/99rh_perl_perf_bug.t
new file mode 100644 (file)
index 0000000..645c115
--- /dev/null
+++ b/t/99rh_perl_perf_bug.t
@@ -0,0 +1,72 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+use Test::More;
+use lib qw(t/lib);
+use DBICTest;
+
+# This is a rather unusual test.
+# It does not test any aspect of DBIx::Class, but instead tests the
+# perl installation this is being run under to see if it is:-
+#  1. Potentially affected by a RH perl build bug
+#  2. If so we do a performance test for the effect of
+#     that bug.
+#
+# You can skip these tests by setting the DBIC_NO_WARN_BAD_PERL env
+# variable
+#
+# If these tests fail then please read the section titled
+# Perl Performance Issues on Red Hat Systems in 
+# L<DBIx::Class::Manual::Troubleshooting>
+
+plan skip_all =>
+  'Skipping RH perl performance bug tests as DBIC_NO_WARN_BAD_PERL set'
+  if ( $ENV{DBIC_NO_WARN_BAD_PERL} );
+
+eval "use Benchmark";
+plan skip_all => 'needs Benchmark for testing' if $@;
+
+plan tests => 2;
+
+{
+    package    # don't want this in PAUSE
+      TestRHBug;
+    use overload bool => sub { 0 }
+}
+
+sub _has_bug_34925 {
+    my %thing;
+    my $r1 = \%thing;
+    my $r2 = \%thing;
+    bless $r1 => 'TestRHBug';
+    return !!$r2;
+}
+
+sub _possibly_has_bad_overload_performance {
+    return $] < 5.008009 && !_has_bug_34925();
+}
+
+ok( !_possibly_has_bad_overload_performance(),
+    'Checking not susceptable to bless/overload performance problem' );
+
+my $results = timethese(
+    0,
+    {
+        overload => sub {
+            use overload q(<) => sub { };
+            my %h;
+            for ( my $i = 0 ; $i < 5000 ; $i++ ) {
+                $h{$i} = bless [] => 'main';
+            }
+        },
+        nooverload => sub {
+            my %h;
+            for ( my $i = 0 ; $i < 5000 ; $i++ ) {
+                $h{$i} = bless [] => 'main';
+            }
+          }
+    }
+);
+
+ok( ( ( $results->{nooverload}->iters / $results->{overload}->iters ) < 2 ),
+    'Overload/bless performance acceptable' )