From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk0-f43.google.com (mail-vk0-f43.google.com [209.85.213.43]) by dpdk.org (Postfix) with ESMTP id D44042956 for ; Thu, 7 Apr 2016 19:58:40 +0200 (CEST) Received: by mail-vk0-f43.google.com with SMTP id c4so109198052vkb.3 for ; Thu, 07 Apr 2016 10:58:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=infinite-io.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=Hgr+TAOV/od9x/fj/LoG9XhpFm1nhullLfGU7gwlUaI=; b=jWMkd3Kg2nAJt676825/zMNXWbbJBud+NhCjH7VOjAV1t+Mw9suIGTxRA3oex+bVn9 Z2iRgTWOaBIXfN8kE0DN2KLDPs3MgVsQ8uZkxLG1QQefc62bO4PlKkv3J+GGQ1QpQGux YCDMfJjQTMItiTGSZxeSv9SRD9myvzW/+1/Osu1Ru24qc7ttjsFypxuHhz92osY9eUdc rJCfwIY+4uQJ11vW1lcbLZtloymgowCG8orqfziuwGgu1/ad/EVQ9apHdN6Y3KvLbvmE m0xoP+Iikf/DN3z8v8kwKnMFKjVgbyk4yzxM1ANDe6D1jiOynyZmnokV8hutkkjRU9NR jJqw== 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=Hgr+TAOV/od9x/fj/LoG9XhpFm1nhullLfGU7gwlUaI=; b=RdXhQj8+1OC1j5AcQ2vh5KNPVuaXXBQVFjoNlT4ryUgB6a0IJ1MTuiem6LuuX7rTyW YyteMf1e0TBJ1y4GBHBYEsDBW713YQTRCYDYB3LdgVh13QlmQ9qdRuNXuyZ7FmYbfwdF mQJRqV5BvjRfNXdGRIG/MQjmdFN0icHfJzYsdBkfmBpnYXPtarnHaUImoPHuX0phl5Wf qN1/TGYIcXeEUcIeHql5Qh1w0vSNq0z4RsOkWU0konYP7FWeMLNsLqXlyAwU+3sllAMq sWNM/qwP/bYQP5ykuLW1Vr/0f0SHeT5JMwYrxiukCW+P7cUgzwlaQW9SIe4wELBbMKGQ 5svw== X-Gm-Message-State: AD7BkJIPlLTmMUU4TEQslDEyg1FI3LMjgUy32WMAGmp5uaTmgSl+20ldCIjbbFtUgcyG0q1IcRHNm9ZWIXDuYw== MIME-Version: 1.0 X-Received: by 10.31.8.68 with SMTP id 65mr2080043vki.150.1460051920228; Thu, 07 Apr 2016 10:58:40 -0700 (PDT) Received: by 10.103.86.14 with HTTP; Thu, 7 Apr 2016 10:58:40 -0700 (PDT) In-Reply-To: <57066FC5.6000900@intel.com> References: <57066FC5.6000900@intel.com> Date: Thu, 7 Apr 2016 12:58:40 -0500 Message-ID: From: Jay Rolette To: Ferruh Yigit Cc: DPDK , Neil Horman Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] Potential deadlock in KNI RX path 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 17:58:41 -0000 On Thu, Apr 7, 2016 at 9:33 AM, Ferruh Yigit wrote: > On 4/6/2016 9:22 PM, Jay Rolette wrote: > > Over a year ago, Neil pointed out that calling netif_rx() from > > kni_net_rx_normal() was a bug and could cause lockups. Here's the > comment: > > > > http://dpdk.org/ml/archives/dev/2015-March/015783.html > > > > Looking at the current code base, it is still calling netif_rx() instead > of > > netif_rx_ni() as suggested. > > > > Did that fall through the cracks or is there disagreement about whether > it > > was the right thing to do? > > > > Thanks, > > Jay > > > Hi Jay, > > Using netif_rx_ni() looks like correct thing to do. I will send a patch > for it. > > But we poll on this function, this means doing lots of > preempt_disable/enable(); which may have a negative effect on > performance. Although I did very brief test and did not observed any > performance degradation. > > It can be great if somebody out already using KNI do some performance > analysis with the patch. > > Another observation, for multiple kthread mode, the ksoftirq threads CPU > consumption removed when switched to netif_rx_ni(), I remember in mail > list somebody complained about ksoftirq CPU usage increase for this case. > Thanks Ferruh. We'll make that change in our local repo and run it through its paces. Jay