From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f176.google.com (mail-wr0-f176.google.com [209.85.128.176]) by dpdk.org (Postfix) with ESMTP id C0AC5AAC2 for ; Tue, 13 Mar 2018 17:16:01 +0100 (CET) Received: by mail-wr0-f176.google.com with SMTP id s18so422718wrg.9 for ; Tue, 13 Mar 2018 09:16:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=T1qE2LPNmMEUsAdd7m+RNu/iCPm3F/Jt4HNXYvqyrPU=; b=oa1xRxHkvFYhVMGvWK/o6v/bjC5N7tl4VrOtw6fIxrfM6DhzrVgBTBU2yRZqSVZNf4 XZs/ifFqKe7AgRgwegDssdxskSZk65yrlVTcZXN+3pinmBuDIjiuo0vla05V4fSgbUMS wZPD6OR2amaQD7g/IxbbCPnGrD0ZYnOuCqsBgyJRK54ACJD5pUu1lziL/ECy3HYCC1mE sJDkO2p+KElxijIXZJARATuNodlF7v3zq3BBOLwzqG98z1/JMKjbiD+XCwcIsahWu1NM 7S9/tGSMP/NiW/wl5/iZVm+aQcgeFXulffzsMdgt0PDtzhjiN5SdomUthx5buBtOX3AY /DyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=T1qE2LPNmMEUsAdd7m+RNu/iCPm3F/Jt4HNXYvqyrPU=; b=nM8zMtLlhlX7pwq4/X29pz55SsiUNycBYASkpg5nIRPdBBdDFEZuDCk5T1Mz3W8TXQ F47OfjWXL9/cRQURcIDVvxWKsv667SSWn+RtjNVrZq0D78XdEU8oionF9k7MEYWxwy5q 1YpvIed23J5xrPJ7wWvInV1T6dM1ABEWhiMuLvLxB+/4dWuCddbH+RwGuM00tLJFn2+E jVFcF3yT8YxeexhJbZoLK/KnAFaJuTQEQKVNCOoEVVp1l4lWJSSQ6w+NaGyJ8xWgoSup uF86shV68nenVUeb39A9TnZnPbn9uTg/PwNDDDpCg3ldKw1I8hBMuO2snBqwXLjWdmxr lyVA== X-Gm-Message-State: AElRT7FUDCBKTJwX5I7kDyP0hp+TtWy/8BUfWoGSUWYQkTw1etLeD02l gnH1VU/+gGrnHmIhE8oMrwXPNjcy2+IS8fLl3hY= X-Google-Smtp-Source: AG47ELtIOiQ6Q3Bjxm8H8CKtnU4dBamxS56dRD8Cie4OaQBd71vwsPs+m6B3pf3M/JW3SWRJpzOopPNx8RExddUPHdg= X-Received: by 10.223.176.171 with SMTP id i40mr1060321wra.246.1520957760703; Tue, 13 Mar 2018 09:16:00 -0700 (PDT) MIME-Version: 1.0 Received: by 10.223.175.202 with HTTP; Tue, 13 Mar 2018 09:16:00 -0700 (PDT) From: Stefan Baranoff Date: Tue, 13 Mar 2018 12:16:00 -0400 Message-ID: To: users@dpdk.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: [dpdk-users] XL710 KVM SR-IOV 4ms/8ms Latency X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Mar 2018 16:16:01 -0000 All, We're seeing an odd 8ms latency under low load through a virtualized DPDK application. Even a very simple, basic, l2fwd style application exhibits this behavior. Our environment is: Host: CentOS 7.4 - fully updated 2 x Intel Gold 6148 CPU 384 GB of RAM in 12 x 32GB configuration Intel XL710 NIC configured for SR-IOV using host PF (driver is CentOS default version) Guest: KVM (libvirt) based - cpu mode = host-model, features = acpi, apic, pae CentOS 7.4 - full updated 8 logic cores 32 GB of RAM 2 DPDK NICs are SR-IOV XL710 VFs passed through Running a single ICMP echo request/response (ping) through an l2fwd equivalent on the VM results in mostly 8ms RTTs with a few sub-1ms RTTs. Switching to a Linux bridge we see sub-1ms latencies. Using the physical function on the physical host with the same application we do not see such latency. Any ideas? Thanks, Stefan