From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Bauch Subject: Re: [PATCH v5 resend 07/12] virtio: resolve for control queue Date: Thu, 8 Oct 2015 22:51:02 +0200 Message-ID: <5616D736.2040108@steffenbauch.de> References: <1442589061-19225-1-git-send-email-yuanhan.liu@linux.intel.com> <1442589061-19225-8-git-send-email-yuanhan.liu@linux.intel.com> <20150920121748-mutt-send-email-mst@redhat.com> <20150921063647.GQ2339@yliu-dev.sh.intel.com> <20151008153205.GB21145@kalyazin.rnd.samsung.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: dev@dpdk.org Return-path: Received: from minos.steffenbauch.de (minos.steffenbauch.de [91.250.119.163]) by dpdk.org (Postfix) with ESMTP id A49C7B62 for ; Thu, 8 Oct 2015 22:51:16 +0200 (CEST) Received: from localhost (localhost.localdomain [127.0.0.1]) by minos.steffenbauch.de (Postfix) with ESMTP id 7B35860B87 for ; Thu, 8 Oct 2015 22:51:16 +0200 (CEST) Received: from minos.steffenbauch.de ([127.0.0.1]) by localhost (minos.steffenbauch.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id t-Bl9plTzqlU for ; Thu, 8 Oct 2015 22:51:16 +0200 (CEST) Received: from [10.1.1.213] (ipb2193648.dynamic.kabel-deutschland.de [178.25.54.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by minos.steffenbauch.de (Postfix) with ESMTPSA id 26DE260B44 for ; Thu, 8 Oct 2015 22:51:16 +0200 (CEST) In-Reply-To: <20151008153205.GB21145@kalyazin.rnd.samsung.ru> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 10/08/2015 05:32 PM, Nikita Kalyazin wrote: > Hi Yuanhan, > > > As I understand, the dead loop happened here (virtio_send_command): > while (vq->vq_used_cons_idx == vq->vq_ring.used->idx) { > rte_rmb(); > usleep(100); > } > > Could you explain why wrong config reading caused that and how correct reading helps to avoid? > Hi, I just recognized that this dead loop is the same one that I have experienced (see http://dpdk.org/ml/archives/dev/2015-October/024737.html for reference). Just applying the changes in this patch (only 07/12) will not fix the dead loop at least in my setup. Best regards, Steffen