sub norm_commit_message {
    my $msg = shift;
    $msg =~ s/^commit .*?$//gm;
    $msg =~ s/^Date:.*?$//gm;
    $msg =~ s/^    Signed-off-by: .*?$//gm;
    $msg =~ s/^.*?cherry picked from commit.*?$//gm;
    $msg =~ s/^\s+$//gm;
    $msg =~ s/^    git-svn-id.*?$//gm;
    return $msg;
}

my %rel_2_0_commits = map { norm_commit_message($_) => 1 } (split /\000/, `git log -z origin/rel_2_0`);
foreach my $commit (split /\000/, `git log -z origin/rel_2_0..origin/rel_2_1`) {
    unless (exists $rel_2_0_commits{norm_commit_message($commit)}) {
        $commit =~ s/\000//;
        print $commit, "\n";
    }
}