deq_now = clib_min (deq_max, svm_fifo_max_read_chunk (app_tx_fifo));
enq_max = svm_fifo_max_enqueue_prod (tls_tx_fifo);
/** There is no engough enqueue space for one record **/
if (enq_max <= record_overhead)
{
deq_now = clib_min (deq_max, svm_fifo_max_read_chunk (app_tx_fifo));
enq_max = svm_fifo_max_enqueue_prod (tls_tx_fifo);
/** There is no engough enqueue space for one record **/
if (enq_max <= record_overhead)
{