[dpdk-dev] [PATCH v3] net/kni: add KNI PMD
ferruh.yigit at intel.com
Fri Nov 4 13:21:32 CET 2016
Thank you for the review.
On 11/3/2016 1:24 AM, Yong Wang wrote:
>> -----Original Message-----
>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Ferruh Yigit
>> Sent: Monday, October 10, 2016 6:20 AM
>> To: dev at dpdk.org
>> Cc: Ferruh Yigit <ferruh.yigit at intel.com>
>> Subject: [dpdk-dev] [PATCH v3] net/kni: add KNI PMD
>> Add KNI PMD which wraps librte_kni for ease of use.
>> KNI PMD can be used as any regular PMD to send / receive packets to the
>> Linux networking stack.
>> Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
>> * rebase on top of latest master
>> * updated driver name eth_kni -> net_kni
> Nit: change this to CONFIG_RTE_LIBRTE_KNI_PMD instead to be consistent with all other pmds.
There is an inconsistency between virtual and physical PMD config options.
Physical ones: xxx_PMD=
*IXGBE_PMD, *I40E_PMD, *ENA_PMD, ...
Virtual ones: PMD_xxx=
*PMD_RING, *PMD_PCAP, *PMD_NULL, ...
So I am consistent with inconsistency J
>> +#define DRV_NAME net_kni
> The name generated this way is not consistent with other vdevs. Why not simply assign "KNI PMD" to drv_name?
Right, it is not consistent but intentionaly.
With macro RTE_PMD_REGISTER_VDEV(net_kni, xxx), rte_driver.name set to
and if you set drivername to "KNI PMD", pmd will report driver name as
so there will be two different driver names, I tried to unify them to a
And some physical drivers already does same thing.
>> +static uint16_t
>> +eth_kni_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
>> + struct pmd_queue *kni_q = q;
>> + struct rte_kni *kni = kni_q->internals->kni;
>> + uint16_t nb_pkts;
>> + nb_pkts = rte_kni_rx_burst(kni, bufs, nb_bufs);
>> + kni_q->rx.pkts += nb_pkts;
>> + kni_q->rx.err_pkts += nb_bufs - nb_pkts;
>> + return nb_pkts;
> I don't think it's safe to do receive from two queues concurrently on two cores sharing the same underlying KNI device due to the current limitation of KNI user-space queues not being multi-thread safe.
You are right, above code is not safe.
It is possible to create a KNI interface per queue, but I don't see any
advantage of this against creating a new virtual KNI port.
So I will limit to single queue.
> Is the proposed plan to have the application layer implement
> If that's the case, it needs to be clearly documented and depending on
the implementation, measurable overhead will be incurred.
> Otherwise (only single-queue supported), could you check queue number
if the application tries to configure multi-queue?
>> +static struct rte_eth_dev *
>> +eth_kni_create(const char *name, unsigned int numa_node)
>> + struct pmd_internals *internals = NULL;
>> + struct rte_eth_dev_data *data;
>> + struct rte_eth_dev *eth_dev;
>> + uint16_t nb_rx_queues = 1;
>> + uint16_t nb_tx_queues = 1;
> Since these two values are always 1 here, I think they could be removed.
I will remove them.
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