From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f195.google.com (mail-io0-f195.google.com [209.85.223.195]) by dpdk.org (Postfix) with ESMTP id F22889AF6 for ; Fri, 20 May 2016 18:45:47 +0200 (CEST) Received: by mail-io0-f195.google.com with SMTP id 190so4989340iow.2 for ; Fri, 20 May 2016 09:45:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=noJ7NkKm0v2IAR0+ZnznqZBWdlguMi4gTkq/HTzTCuM=; b=z2yyBjT4H+UJ5Yo362TXcb0DLnSVxtKxEZ2qNqvSLvGfSziE94gcVewX/7veX7Gb/t alv8QOc0xPDRxqD1pVgtNiLWNABPNPAIRAb05DEnTTCWeAW+QS0BUgtdHwXDorijzfe9 Zla/a/8dcSQ6x2mWGp8Y933NCiaNn3GVd0GZ1Ogc6C5m7WLI87UQPQ+4GeXWZbTyd5dm WOC4byoUbmeET7yJNSmrkVosHCvl5gyx7HzfNly5Sta0992GwLKOX55lk7TNKkI9w8Ae bq+Z4hgxW6bHW9tx2K/qtzidD5lQTj1MAIKhz5vC4TQbJXdcOOwHGxl0nJqsxEavEYo5 X3Lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc; bh=noJ7NkKm0v2IAR0+ZnznqZBWdlguMi4gTkq/HTzTCuM=; b=Ogbk5hcNE1AeCluUnPhTQujMBkHrL8/5mLx4XNSajVdGE5H08xWuC9GTaf8NkGEE0x APsMzaAp3KsTB2IPQoFnxMMlZkL/lVl9Xqbeks3/WXcvvFlGB5TjCBzNx7sGTm8z8Gwv KrUY+ltFKyutU17+J3FndkS1GRc12tVkvWsrePkUo3FCHqQy1DEMPjMUtE1sHkc6bW6V 5E3lUxzSq2Z9YSiFI6lKEFAVseXMHp0646gBi+uRdinEXTFrD00h4V6y2a9chRJOYICe E92gA84csfdcPPsnWJkhB/J9XntwofCZKgPeCtKBuA2QaF9pJkH+CL+/P1wLycJ1hNQ2 5WoA== X-Gm-Message-State: AOPr4FX1Z+cKq/Lz88KhITcR3J+WxSk7DiFueNr+yp1+ZBJAybS77O5Ovb8Q6sa6KKqZP9nkKKrErGLZKry1+g== MIME-Version: 1.0 X-Received: by 10.107.25.13 with SMTP id 13mr3810017ioz.104.1463762747455; Fri, 20 May 2016 09:45:47 -0700 (PDT) Received: by 10.36.143.5 with HTTP; Fri, 20 May 2016 09:45:47 -0700 (PDT) In-Reply-To: References: Date: Fri, 20 May 2016 09:45:47 -0700 Message-ID: From: Alexander Duyck To: SwamZ Cc: dev@dpdk.org Content-Type: text/plain; charset=UTF-8 Subject: Re: [dpdk-dev] Rx_missed_errors drops with larger packet size X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 May 2016 16:45:48 -0000 On Fri, May 20, 2016 at 2:09 AM, SwamZ wrote: > Hi, > > > While doing performance testing with larger packet size (like 4000 bytes), > we are seeing rx_missed_errors on the interface. This issue is not seen > with packet size less than 2000. There were questions asked in this forum > on rx_missed_error, but there was not any conclusion. Please let me know > what could be the reason for these drops. > > > I tried the following without any luck: > > 1) Tried different burst size like 16, 32 an 64 > > 2) Tried different number of the rx descriptors like 512, 1024, 2048 and > 4096. I've seen issues like this occur on the 82599 using the Linux kernel diver in the past, but it was usually related to CPU C states. I'm assuming that shouldn't apply since you are using the poll mode driver right so there are no interrupts and the CPUs are busy polling. Another thing to check is that you have sufficient PCIe bandwidth. Take a look at an lspci -vvv for the device and make certain it is connected at x8 Gen2. > Setup and testing details: > > CPU Speed : 2.6 GHz > > NIC : 82599ES 10-Gigabit > > IO Virtualization: SR-IOV > > IO and packet processing cores are in the same NUMA. If you are running SR-IOV then the SRRCTL_DROP_EN bit should be set in all the SRRCTL registers if I am not mistaken. As such if you are triggering Rx missed errors it may not be related to the driver directly but could point to some sort of PCIe but utilization issue. How many VFs are you using and is any of this traffic multicast or broadcast? Multicast or broadcast traffic can potentially saturate the PCIe bus if there is enough of it on the wire as each packet is normally replicated for each active VF. So 1 packet on the wire (4K) can become 8 on the PCIe bus (32K) if you have 7 active VFs. > Packet size : 4000 bytes > > Traffic rate: 80 % line rate. If the traffic rate is < ~80% then drops are > not seen. > > Application: This is a sample application developed using L3fwd example app. > > DPDK version: 1.7 > Thanks, > Swamy