[dpdk-dev] drops while transmitting to the kni using rte_kni_tx_burst()
ferruh.yigit at intel.com
Tue Jan 17 18:57:04 CET 2017
On 1/17/2017 5:46 PM, Ferruh Yigit wrote:
> On 1/16/2017 2:58 PM, Shirley Avishour wrote:
>> I am currently using the kernel interface for recording the received
>> traffic by duplicating the received packets and sending a copy to the
>> kni (and performing pcap_open_live on the kni).
>> my goal rate is around 500Mbps. is it possible to achieve it via the kni ??
> According quick experiment,
> - with kni module lo_mode_fifo_skb (which send all received packets to
> tx, but allocating and copying data to skb to be more realistic)
> - single kernel thread
> - kernel thread bind to a core
> - using kni sample app
> - With small packets
> Best numbers get when rx,tx and kernel cores are in same socket with the
> NIC, it is ~1.7Mpps (million packet per second)
> When KNI_RX_LOOP_NUM increased to 10000, it becomes ~1.9Mpps.
And again, very quick test, between two KNI ports, with kni sample app,
using iperf default values, gives ~3 Gbits/sec
>> On Mon, Jan 16, 2017 at 4:55 PM, Ferruh Yigit <ferruh.yigit at intel.com
>> <mailto:ferruh.yigit at intel.com>> wrote:
>> On 1/16/2017 2:47 PM, Shirley Avishour wrote:
>> > Hi,
>> > As I wrote the kernel thread runs on a dedicated lcore.
>> > running top while my application is running I see kni_single and the cpu
>> > usage is really low...
>> > Is there any rate limitation for transmitting to the kernel interface
>> > (since packets are being copied in the kernel).
>> Yes, kind of, kernel thread sleeps periodically, with a value defined by
>> KNI_KTHREAD_RESCHEDULE_INTERVAL. You can try tweaking this value, if you
>> want thread do more work, less sleep J
>> Also KNI_RX_LOOP_NUM can be updated for same purpose.
>> > On Mon, Jan 16, 2017 at 4:42 PM, Ferruh Yigit <ferruh.yigit at intel.com <mailto:ferruh.yigit at intel.com>
>> > <mailto:ferruh.yigit at intel.com <mailto:ferruh.yigit at intel.com>>>
>> > On 1/16/2017 12:20 PM, Shirley Avishour wrote:
>> > > Hi,
>> > > I have an application over dpdk which is consisted of the
>> following threads
>> > > each running on a separate core:
>> > > 1) rx thread which listens on in a poll mode for traffic
>> > > 2) 2 packet processing threads (for load balancing)
>> > > 3) kni thread (which also runs on a separate core).
>> > This is kernel thread, right? Is it bind to any specific core?
>> > Is it possible that this thread shares the core with 2nd
>> > thread when enabled?
>> > >
>> > > the rx thread receives packets and clones them and transmit
>> a copy
>> > to the
>> > > kni and the other packet is sent to the packet processing unit
>> > (hashing
>> > > over 2 threads).
>> > > the receive traffic rate is 100Mbps.
>> > > When working with single packet processing thread I am able
>> to get
>> > all the
>> > > 100Mbps towards the kni with no drops.
>> > > but when I activate my application with 2 packet processing
>> > threads I start
>> > > facing drops towards the kni.
>> > > the way I see it the only difference now is that I have another
>> > threads
>> > > which handles an mbuf and frees it once processing is completed.
>> > > Can anyone assist with this case please?
>> > >
>> > > Thanks!
>> > >
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