Hi Masoud, Try a low latency kernel (i.e. linux-image-lowlatency). Andriy
On Mon, Jan 25, 2016 at 2:15 PM, Masoud Moshref Javadi <masood.moshref.j at gmail.com> wrote: > 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 >> -- Andriy Berestovskyy
