The need to recompile the three patterns each time through the outer loop is probably what's taking extra time. You could compile them once with qr, @patterns = map qr/\Q$_\E/, @patterns; or test lines of interest with index, since the patterns seem to be constant,

        foreach my $pattern (@patterns)
        {
            if (-1 != index $line, $pattern)
            {
                push(@events, $line);
                last;
            }
        }
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I think the fastest way is to avoid the inner loop and gain the speed of hash lookup like this:

chomp @$srcRef;
my %pattern;
@pattern{@patterns} = ();
my @events = grep {exists $pattern{$_}} @$srcRef;
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That solution depends on there being no other content in the @$srcRef lines, besides the chomped line ends.