#Merge cases#

In the consumer, you have two separate checks:

 if ((seqno)-1 == count) {
 /* the message hasn't been completed yet */
 _mm_pause();
 continue;
 }

and later:

 if (consumer_count > count) {
 /* we have incremented the consumer count enough to catch up to the producer */
 _mm_pause();
 continue;
 }

Since consumer_count doesn't change in between those two blocks of code, you could move the second check up and merge it with the first one:

 if ((seqno)-1 == count || consumer_count > count) {
 /* the message hasn't been completed yet, or we have */
 /* incremented the consumer count enough to catch up to the producer */
 _mm_pause();
 continue;
 }

Moving the second check up could actually help you avoid dropping a packet that didn't need to be dropped.

Merge cases

In the consumer, you have two separate checks:

 if ((seqno)-1 == count) {
 /* the message hasn't been completed yet */
 _mm_pause();
 continue;
 }

and later:

 if (consumer_count > count) {
 /* we have incremented the consumer count enough to catch up to the producer */
 _mm_pause();
 continue;
 }

Since consumer_count doesn't change in between those two blocks of code, you could move the second check up and merge it with the first one:

 if ((seqno)-1 == count || consumer_count > count) {
 /* the message hasn't been completed yet, or we have */
 /* incremented the consumer count enough to catch up to the producer */
 _mm_pause();
 continue;
 }

Moving the second check up could actually help you avoid dropping a packet that didn't need to be dropped.