[dpdk-dev] drops while transmitting to the kni using rte_kni_tx_burst()
ferruh.yigit at intel.com
Tue Jan 17 18:46:25 CET 2017
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.
> 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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