From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f176.google.com (mail-qk0-f176.google.com [209.85.220.176]) by dpdk.org (Postfix) with ESMTP id 10FDCB62 for ; Mon, 25 Jan 2016 14:49:17 +0100 (CET) Received: by mail-qk0-f176.google.com with SMTP id s5so54187696qkd.0 for ; Mon, 25 Jan 2016 05:49:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-type; bh=AtWTi9/zOaLsb3mFZkBywIn/oiBPobabnE5gXk72hxA=; b=hLUjvmEV9/8ZEilpWNSj8CTu6293YbfqHjZ8WPd8/nZGhf4LpWd3dBRL8r1i9ZsqUT Nt1avTajSWclB0pKuSjpjbuMai2FABYytPcmXVqqQNlPauQ/gj4FoQu7DEpUt4aeN1QM 4GziH1kNeVBl3xHxYdcf7bV3OEM6vN7s+p9jLlpp6FW/M8G2NWQSh0UFauBXZ2ttL/qX 2etzye602JA7QByHByZN3ZR7W3mRyfLNiWiSKG0z8dOhTC32Ai6In0qk4jHtKfA4rmyM F6ZkgNYuhGRZ/F1M9UvS3OpBo2YH24xcldHKAxxZK1vzWJv3n8t1d90DiNpFupER5Stk voSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type; bh=AtWTi9/zOaLsb3mFZkBywIn/oiBPobabnE5gXk72hxA=; b=aKWy3bPrIoqp0HV3SctSupZ6Fwlv9RU9m89OXVtUnSn2bq64jn3gRZ5XRPXZ/ckE58 BNKV0UX+1DA59PBF1M0hp8WftC74B2zU5jEcskdEVQpL84P71MZdfmGqvKzu+Ey5eLVg VkdafnNYPEQXbts9mYOM24DufLtD2A+qu1cI3068VnLcKC0W+wJZziik/XXUxRphJ0Ci Wuae9vMvp89cJ9qZULewdlrohJNl5Atmx0tBj7MRfcpMfZcVr2LIv0OTjzSnMfBUoEjO hh8t71onivVmFdMvytVXU0rA7mRzX9pTmQEiUlWW+uTwIGJXCwQgjuZyFds5/fJldeCU Xj7w== X-Gm-Message-State: AG10YOSisUt7sF9YCW3DsTGTVV9efg2GbpXjxCtkq3M1lgm4qPzsS2iVYaUtstXIJyUylVhPdsDVzWLB7Q6v9g== X-Received: by 10.55.212.89 with SMTP id l86mr11455396qki.8.1453729756553; Mon, 25 Jan 2016 05:49:16 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Masoud Moshref Javadi Date: Mon, 25 Jan 2016 13:49:06 +0000 Message-ID: To: Andriy Berestovskyy Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: "users@dpdk.org" Subject: Re: [dpdk-users] high jitter in dpdk kni X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jan 2016 13:49:17 -0000 Thanks. For me the easiest solution is to sacrifice a core and set CONFIG_RTE_KNI_PREEMPT_DEFAULT to 'n'. I can confirm that this reduced the delay to 0.1ms On Mon, Jan 25, 2016 at 5:43 AM Andriy Berestovskyy wrote: > 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 > 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@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@nokia.com > >> > >> -----Original Message----- > >> From: users [mailto:users-bounces@dpdk.org] On Behalf Of EXT Masoud > >> Moshref Javadi > >> Sent: samedi 23 janvier 2016 15:18 > >> To: users@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 >