From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by dpdk.org (Postfix) with ESMTP id A6B5D5A33 for ; Tue, 25 Aug 2015 19:39:30 +0200 (CEST) Received: by wicne3 with SMTP id ne3so22147793wic.0 for ; Tue, 25 Aug 2015 10:39:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-type :content-transfer-encoding; bh=SpDdWPohHrhaIghE+LKJ9uM7tTuhrYBt6cGbd6T5cec=; b=aWxE5/PhWFM4T3YkUpiOjPpXe6AfPGVKqHlwDskHu6WSYojuwFB9WRyE42yJnVWMGV Px2yLJIsmlkb5ALk65G54qHIvO+YgRzTCnCTRre/scUn/Tvb0ndBkrlbSXd02Bjp3Jqw /BZviTYRMvTiIpTbhJVkq6b/f0HSXUiLSXVxBlnNDPMHe0NaEnkvXlkWli5fPvlw1mBc ZjT9ezel+8/vWfzYjgC/nNwvsBJ1YNqJBjUG+Rvde3Mj7gdr5WbLgiFNGei+37OEdpW6 nhwM4kWa3djniSGvBDNLHvt0wcH/Xu+kctFotY2f/lC1cD5V0b60bK07d1+zCU7iL855 KPwg== X-Gm-Message-State: ALoCoQlzyOeekaOqthSZV7TWPQr7ZJU8OVJcab93upl4BvF8cnhlzGTwKngbWO84rx4UgwM5iEcO X-Received: by 10.194.187.36 with SMTP id fp4mr55850922wjc.88.1440524370503; Tue, 25 Aug 2015 10:39:30 -0700 (PDT) Received: from avi.cloudius ([37.142.229.250]) by smtp.googlemail.com with ESMTPSA id j7sm29107422wjz.11.2015.08.25.10.39.28 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 25 Aug 2015 10:39:29 -0700 (PDT) To: "Ananyev, Konstantin" , Vlad Zolotarov , "Lu, Wenzhuo" References: <1439489195-31553-1-git-send-email-vladz@cloudius-systems.com> <55CD7EA5.6060100@cloudius-systems.com> <6A0DE07E22DDAD4C9103DF62FEBC0909D3E116@shsmsx102.ccr.corp.intel.com> <2601191342CEEE43887BDE71AB97725836A76983@irsmsx105.ger.corp.intel.com> <55D4543E.9000808@cloudius-systems.com> <2601191342CEEE43887BDE71AB97725836A7BEC4@irsmsx105.ger.corp.intel.com> <55D59639.7070206@cloudius-systems.com> <55D59852.30002@cloudius-systems.com> <55D598AA.50209@cloudius-systems.com> <2601191342CEEE43887BDE71AB97725836A7F7B5@irsmsx105.ger.corp.intel.com> From: Avi Kivity Message-ID: <55DCA850.9050605@cloudius-systems.com> Date: Tue, 25 Aug 2015 20:39:28 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <2601191342CEEE43887BDE71AB97725836A7F7B5@irsmsx105.ger.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v1] ixgbe_pmd: forbid tx_rs_thresh above 1 for all NICs but 82598 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: Tue, 25 Aug 2015 17:39:30 -0000 On 08/25/2015 08:33 PM, Ananyev, Konstantin wrote: > Hi Vlad, > >> -----Original Message----- >> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com] >> Sent: Thursday, August 20, 2015 10:07 AM >> To: Ananyev, Konstantin; Lu, Wenzhuo >> Cc: dev@dpdk.org >> Subject: Re: [dpdk-dev] [PATCH v1] ixgbe_pmd: forbid tx_rs_thresh above 1 for all NICs but 82598 >> >> >> >> On 08/20/15 12:05, Vlad Zolotarov wrote: >>> >>> On 08/20/15 11:56, Vlad Zolotarov wrote: >>>> >>>> On 08/20/15 11:41, Ananyev, Konstantin wrote: >>>>> Hi Vlad, >>>>> >>>>>> -----Original Message----- >>>>>> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com] >>>>>> Sent: Wednesday, August 19, 2015 11:03 AM >>>>>> To: Ananyev, Konstantin; Lu, Wenzhuo >>>>>> Cc: dev@dpdk.org >>>>>> Subject: Re: [dpdk-dev] [PATCH v1] ixgbe_pmd: forbid tx_rs_thresh >>>>>> above 1 for all NICs but 82598 >>>>>> >>>>>> >>>>>> >>>>>> On 08/19/15 10:43, Ananyev, Konstantin wrote: >>>>>>> Hi Vlad, >>>>>>> Sorry for delay with review, I am OOO till next week. >>>>>>> Meanwhile, few questions/comments from me. >>>>>> Hi, Konstantin, long time no see... ;) >>>>>> >>>>>>>>>>>> This patch fixes the Tx hang we were constantly hitting with a >>>>>>>> seastar-based >>>>>>>>>>>> application on x540 NIC. >>>>>>>>>>> Could you help to share with us how to reproduce the tx hang >>>>>>>>>>> issue, >>>>>>>> with using >>>>>>>>>>> typical DPDK examples? >>>>>>>>>> Sorry. I'm not very familiar with the typical DPDK examples to >>>>>>>>>> help u >>>>>>>>>> here. However this is quite irrelevant since without this this >>>>>>>>>> patch >>>>>>>>>> ixgbe PMD obviously abuses the HW spec as has been explained >>>>>>>>>> above. >>>>>>>>>> >>>>>>>>>> We saw the issue when u stressed the xmit path with a lot of >>>>>>>>>> highly >>>>>>>>>> fragmented TCP frames (packets with up to 33 fragments with >>>>>>>>>> non-headers >>>>>>>>>> fragments as small as 4 bytes) with all offload features enabled. >>>>>>> Could you provide us with the pcap file to reproduce the issue? >>>>>> Well, the thing is it takes some time to reproduce it (a few >>>>>> minutes of >>>>>> heavy load) therefore a pcap would be quite large. >>>>> Probably you can upload it to some place, from which we will be able >>>>> to download it? >>>> I'll see what I can do but no promises... >>> On a second thought pcap file won't help u much since in order to >>> reproduce the issue u have to reproduce exactly the same structure of >>> clusters i give to HW and it's not what u see on wire in a TSO case. >> And not only in a TSO case... ;) > I understand that, but my thought was you can add some sort of TX callback for the rte_eth_tx_burst() > into your code that would write the packet into pcap file and then re-run your hang scenario. > I know that it means extra work for you - but I think it would be very helpful if we would be able to reproduce your hang scenario: > - if HW guys would confirm that setting RS bit for every EOP packet is not really required, > then we probably have to look at what else can cause it. > - it might be added to our validation cycle, to prevent hitting similar problem in future. > Thanks > Konstantin > I think if you send packets with random fragment chains up to 32 mbufs you might see this. TSO was not required to trigger this problem.