volatile struct app_stats {
	struct {
		uint64_t rx_pkts;
		uint64_t enqueue_pkts;
		uint64_t enqueue_failed_pkts;
	} rx __rte_cache_aligned;

	struct {
		uint64_t dequeue_pkts;
		uint64_t enqueue_pkts;
		uint64_t enqueue_failed_pkts;
	} wkr __rte_cache_aligned;

	struct {
		uint64_t dequeue_pkts;
		/* Too early pkts transmitted directly w/o reordering */
		uint64_t early_pkts_txtd_woro;
		/* Too early pkts failed from direct transmit */
		uint64_t early_pkts_tx_failed_woro;
		uint64_t ro_tx_pkts;
		uint64_t ro_tx_failed_pkts;
	} tx __rte_cache_aligned;
} app_stats;

....
while (!quit_signal) {

		/* dequeue the mbufs from rx_to_workers ring */
		burst_size = rte_ring_dequeue_burst(ring_in,
				(void *)burst_buffer, MAX_PKTS_BURST, NULL);
		if (unlikely(burst_size == 0))
			continue;

		__sync_fetch_and_add(&app_stats.wkr.dequeue_pkts, burst_size);

		/* just do some operation on mbuf */
		for (i = 0; i < burst_size;)
			burst_buffer[i++]->port ^= xor_val;

		/* enqueue the modified mbufs to workers_to_tx ring */
		ret = rte_ring_enqueue_burst(ring_out, (void *)burst_buffer,
				burst_size, NULL);
		__sync_fetch_and_add(&app_stats.wkr.enqueue_pkts, ret);
		if (unlikely(ret < burst_size)) {
			/* Return the mbufs to their respective pool, dropping packets */
			__sync_fetch_and_add(&app_stats.wkr.enqueue_failed_pkts,
					(int)burst_size - ret);
			pktmbuf_free_bulk(&burst_buffer[ret], burst_size - ret);
		}
	}