Untested, but maybe a hint to a better solution :)

my $matched = 0;
my $blah1;
foreach (@lines) {
    if (m/^request\(.+$/) {
        $blah1 = $1;
        matched = 1;
        next;
    }
    if (m/^s+START_TIME,(.+)$/ && $matched) {
        print $blah1,':',$1;
    }
    $matched = 0;
}
[download]

regards,
tomte

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.