> On Nov 13, 2017, at 2:39 PM, Adrien Mazarguil <adrien.mazarg...@6wind.com> > wrote: > > On Sat, Nov 11, 2017 at 09:18:45PM +0400, Ilya Matveychikov wrote: >> Folks, >> >> Are you serious with it: >> >> typedef uint16_t (*eth_rx_burst_t)(void *rxq, >> struct rte_mbuf **rx_pkts, >> uint16_t nb_pkts); >> typedef uint16_t (*eth_tx_burst_t)(void *txq, >> struct rte_mbuf **tx_pkts, >> uint16_t nb_pkts); >> >> I’m not surprised that every PMD stores port_id in every and each queue as >> having just the queue as an argument doesn’t allow to get the device. So the >> question is - why not to use something like: >> >> typedef uint16_t (*eth_rx_burst_t)(void *dev, uint16_t queue_id, >> struct rte_mbuf **rx_pkts, >> uint16_t nb_pkts); >> typedef uint16_t (*eth_tx_burst_t)(void *dev, uint16_t queue_id, >> struct rte_mbuf **tx_pkts, >> uint16_t nb_pkts); > > I assume it's since the rte_eth_[rt]x_burst() wrappers already pay the price > for that indirection, doing it twice would be redundant.
No need to do it twice, agree. We can pass dev pointer as well as queue, not just the queue’s index. > > Basically the cost of storing a back-pointer to dev or a queue index in each > Rx/Tx queue structure is minor compared to saving a couple of CPU cycles > wherever we can. Not sure about it. More data to store - more cache space to occupy. Note that every queue has at least 4 bytes more than it actually needs. And RTE_MAX_QUEUES_PER_PORT is defined by it’s default to 1024. So we may have 4k extra for each port.... > > I'm not saying its the only solution nor the right approach, it's only one > possible explanation for this API. Thank you for your try.
