[dpdk-users] A question about 82599 nic

[chupenghong]

Hello,

I wonder that  how  the 82599 nic  decides whether the descriptor ring is full or empty. 

The 82599 datasheet says that  the head register equals tail register means that the ring is empty. Howerver, I think that the head register also equals tail register when the ring is full.  

Is it possible the 82599 nic uses the DD flag to distinguish between the full ring and the empty ring ?


Anyone gives me some tips ?


Thanks
Javin