From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by dpdk.org (Postfix) with ESMTP id C4B7B2986 for ; Thu, 7 Apr 2016 21:24:01 +0200 (CEST) Received: by mail-pa0-f41.google.com with SMTP id fe3so60140765pab.1 for ; Thu, 07 Apr 2016 12:24:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=versa-networks-com.20150623.gappssmtp.com; s=20150623; h=from:subject:message-id:date:to:mime-version; bh=Erarmt/OKIru8n1SxNRbLJZ101Qagvz+7N36J9lnS6s=; b=gPS9qxAskzt+nuEF59/6otuWbWrvozFuaXTlAjIguPZv8V4p0JNqc+taCS2VFkAq9+ u5xlbcDa2PjrO4k0TPWPXcpFGAFjF8xfVPAtt7YGCDHbVxH5KNjd9roVx/A6bkzOLoYN RyUAEiYrOVx7bNfpkYFjXgwDHbcwOl/KoayK7ftiYyEQ1IuCr3yYRwCUdIwaJ3P5JggO s6i7oQzp0T8ZDaDIsZLcCMtovIk9nJ5j7BcveCh2r+GM78gs2SkeE3OotU+tD207W35J pxqktI5mKEB0uP5/pkJ7LEMw3B7Ni/JBGz57uukvqlcD17xOVw2u7WWcP+bXDcTEljbw ZWxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:subject:message-id:date:to:mime-version; bh=Erarmt/OKIru8n1SxNRbLJZ101Qagvz+7N36J9lnS6s=; b=Zb/rNP2BmDsi2XbeduDuEkCHIF1GWQ6JfT7UIFfmN8fLVAMZtu+F9UXdjQV7Aey93X zFkAOW91niJQ6DKj7t+zGYppVqt0/LzrhyuLt1StFBDdmlxVRUglxfWbgjL7k/8OivoI 2ZDllZiC9CVx5h6zY+lFlIp4Ng/3Qdrj/TXDEeP7Z8o2ghpwMLVYbO1u681964GeAFfW U9f3lZJ0w+GPAc9bIm7/W6YJ6kJQ7Oqh17wC01wuIqcFyGXzkyUqfjKGnIOvjm+X8ftl ZKO32uM5d2i/7I+Yl0y2CUSiHCGWSZHqxXsPDul2SkuaU3oqL9/NX3MdLhRp7bse2TIo yRTw== X-Gm-Message-State: AD7BkJJvCt+jXut87fjk9o09yQKCPb/8i/SwP3+M57MX7u+X4GBnqUZxpxYy0Wms+Sz8oLVG X-Received: by 10.66.159.232 with SMTP id xf8mr6895238pab.71.1460057041131; Thu, 07 Apr 2016 12:24:01 -0700 (PDT) Received: from [10.0.0.48] (70-35-56-62.static.wiline.com. [70.35.56.62]) by smtp.gmail.com with ESMTPSA id ud5sm13945127pac.11.2016.04.07.12.24.00 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 07 Apr 2016 12:24:00 -0700 (PDT) From: "Sridhar.V.Iyer" Message-Id: Date: Thu, 7 Apr 2016 12:24:04 -0700 To: dev@dpdk.org Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) X-Mailer: Apple Mail (2.3112) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: [dpdk-dev] Packet drops at lower tc transmit-rates. 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: Thu, 07 Apr 2016 19:24:02 -0000 Hi all, We are using DPDK 1.7 in our application. We are running into an issue where a lower transmit-rate configured at = the traffic class of a subport is causing complete packet drops.=20 Here are few parameters to clear up some context: Packet length =3D 728 byte Port rate =3D 1Gbps =3D 12500000 bytes/s Subport tc_period =3D 10 ms=20 Configured TC0 rate =3D 500 kbps =3D 62500 bytes/s This means that for the given subport tc0_credits_per_period =3D 10 * = 62500 / 1000 =3D 625 (from rte_sched_subport_config) Now, there is no token bucket at the subport-tc level, so there are no = credits to accrue. The tc0_credits are just initialized to 625. - This means that we=E2=80=99ll never have =E2=80=9Cenough_credits=E2=80=9D= in grinder_credits_check to process a 728 byte packet. - grinder_schedule will then return 0. - grinder_handle will return 0. - which implies that the rte_sched_port_dequeue will never = dequeue any packet. - After port->time exceeds the subport->tc_time, tc0_credit will be = re-initialized back to 625 again. Is this a bug in the logic? What are some of the viable workarounds? Is this issue taken care of in the later releases? Regards, Sridhar V Iyer