I see. But this should not be the issue in Ping. By the way, I checked the timestamps of sending and receiving times at the kni sample application (kni_ingress and kni_egress methods). The RTT at that level is OK (0.1ms) and it seems the jitter comes from the kni kernel module.
On Mon, Jan 25, 2016 at 12:29 AM Freynet, Marc (Nokia - FR) < marc.freynet at nokia.com> wrote: > Hi, > > Some months ago we had a problem with the KNI driver. > Our DPDK application forwards to the Linux kernel through KNI the SCTP PDU > received from the Eth NIC. > In one configuration, the SCTP port Source and Destination were constant > on all SCTP connections. > This is a known SCTP issue as in the multi processor environment, the SCTP > stack uses the port Source and Destination to hash the processor that will > run the SCTP context in the kernel. > SCTP cannot use the IP address as a hash key thanks to the SCTP multi > homing feature. > > As all SCTP PDU on all SCTP connections where processed by the same Core, > this creates a bottle neck and the KNI interface starts creating Jitter and > even was losing PDU when sending the SCTP PDU to the IP Linux kernel stack. > > I am wondering if in a previous release it you not be possible to add KNI > a kind of load sharing with different queues on different cores to forward > the received PDU to the IP Linux stack. > > ?"Bowl of rice will raise a benefactor, a bucket of rice will raise a > enemy.", Chinese proverb. > > FREYNET Marc > Alcatel-Lucent France > Centre de Villarceaux > Route de Villejust > 91620 NOZAY France > > Tel: +33 (0)1 6040 1960 > Intranet: 2103 1960 > > marc.freynet at nokia.com > > -----Original Message----- > From: users [mailto:users-bounces at dpdk.org] On Behalf Of EXT Masoud > Moshref Javadi > Sent: samedi 23 janvier 2016 15:18 > To: users at dpdk.org > Subject: [dpdk-users] high jitter in dpdk kni > > I see jitter in KNI RTT. I have two servers. I run kni sample application > on one, configure its IP and ping an external interface. > > sudo -E build/kni -c 0xaaaa -n 4 -- -p 0x1 -P --config="(0,3,5)" > sudo ifconfig vEth0 192.168.1.2/24 > ping 192.168.1.3 > > This is the ping result: > 64 bytes from 192.168.1.2: icmp_seq=5 ttl=64 time=1.93 ms > 64 bytes from 192.168.1.2: icmp_seq=6 ttl=64 time=0.907 ms > 64 bytes from 192.168.1.2: icmp_seq=7 ttl=64 time=3.15 ms > 64 bytes from 192.168.1.2: icmp_seq=8 ttl=64 time=1.96 ms > 64 bytes from 192.168.1.2: icmp_seq=9 ttl=64 time=3.95 ms > 64 bytes from 192.168.1.2: icmp_seq=10 ttl=64 time=2.90 ms > 64 bytes from 192.168.1.2: icmp_seq=11 ttl=64 time=0.933 ms > > The ping delay between two servers without kni is 0.170ms. > I'm using dpdk 2.2. > > Any thought on how to keep KNI delay predictable? > > Thanks >
