def compose_config(self):
        """ compose benchmark block """
        # step file
        self.stepper_wrapper.prepare_stepper()
        self.stpd = self.stepper_wrapper.stpd
        if self.stepper_wrapper.instances:
            self.instances = self.stepper_wrapper.instances

        if not self.stpd:
            raise RuntimeError("Cannot proceed with no STPD file")

        kwargs = {}
        kwargs['sequence_no'] = self.sequence_no
        if self.ssl:
            _auth_section = ''
            _ciphers = ''
            ssl_template = "transport_t ssl_transport = transport_ssl_t {\n" \
                           "                timeout = 1s\n" \
                           "                %s\n" \
                           "                %s}\n" \
                           "                transport = ssl_transport"

            if self.client_certificate or self.client_key:
                _auth_section = 'auth_t def_auth = auth_t { key = "%s" cert = "%s"} auth = def_auth' \
                                % (self.client_key, self.client_certificate)
            if self.client_cipher_suites:
                _ciphers = 'ciphers = "%s"' % self.client_cipher_suites
            kwargs['ssl_transport'] = ssl_template % (_auth_section, _ciphers)
        else:
            kwargs['ssl_transport'] = ""
        kwargs['method_stream'] = self.method_prefix + \
            "_ipv6_t" if self.ipv6 else self.method_prefix + "_ipv4_t"
        kwargs['phout'] = self.phout_file
        kwargs['answ_log'] = self.answ_log
        kwargs['answ_log_level'] = self.answ_log_level
        kwargs['comment_answ'] = "# " if self.answ_log_level == 'none' else ''
        kwargs['stpd'] = self.stpd
        kwargs['source_log_prefix'] = self.source_log_prefix
        kwargs['method_options'] = self.method_options
        if self.tank_type:
            kwargs[
                'proto'] = "proto=http_proto%s" % self.sequence_no if self.tank_type == 'http' else "proto=none_proto"
            kwargs['comment_proto'] = ""
        else:
            kwargs['proto'] = ""
            kwargs['comment_proto'] = "#"

        if self.gatling:
            kwargs['bind'] = 'bind={ ' + self.gatling + ' }'
        else:
            kwargs['bind'] = ''
        kwargs['ip'] = self.resolved_ip
        kwargs['port'] = self.port
        kwargs['timeout'] = self.timeout
        kwargs['instances'] = self.instances
        tune = ''
        if self.phantom_http_entity:
            tune += "entity = " + self.phantom_http_entity + "\n"
        if self.phantom_http_field:
            tune += "field = " + self.phantom_http_field + "\n"
        if self.phantom_http_field_num:
            tune += "field_num = {}\n".format(self.phantom_http_field_num)
        if self.phantom_http_line:
            tune += "line = " + self.phantom_http_line + "\n"
        if tune:
            kwargs['reply_limits'] = 'reply_limits = {\n' + tune + "}"
        else:
            kwargs['reply_limits'] = ''

        if self.is_main:
            fname = 'phantom_benchmark_main.tpl'
        else:
            fname = 'phantom_benchmark_additional.tpl'
        template_str = resource_string(
            __name__, "config/" + fname)
        tpl = string.Template(template_str)
        config = tpl.substitute(kwargs)

        return config
compose benchmark block