From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <avi@cloudius-systems.com> Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com [209.85.212.170]) by dpdk.org (Postfix) with ESMTP id 9A83B5952 for <dev@dpdk.org>; Tue, 25 Aug 2015 21:23:49 +0200 (CEST) Received: by widdq5 with SMTP id dq5so24127453wid.0 for <dev@dpdk.org>; Tue, 25 Aug 2015 12:23:49 -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=C2O3l7RP16YqYlHSlh7HzPYb0pbijO4wv4YrKpYo/Ao=; b=PTRFxmP3wo1eUNsWND8hiKIFIRBttUNpDFJF4IRe+dfs/r70bUud+I391Uzr2o9Uia ZeNR/EepoSxeNu+mPfMW5rWQeQLXIj477AUvH8Jl/F4zSs/4fYIJCroS2SKq1Ik7djJF Q3UtoWEzbxbMb+0H9Cxjt8VP5V+BfoQWr6gtPXbSbhNP74sYaqMHmbv0bXNpIMB2JK5N xIJVA0SEZUzKUTLC/zDwnhUxlp8yNZHdAgcAL/bPwRXBNeZhh+vbVqFWiOYBYAGgG0NT mD1wh/Nl4czRHiek7eDE1YHWhiK5XVTo0bV7F8UBKvTeMSIBcCzygBoBboT2sA3VPzw3 Ki0g== X-Gm-Message-State: ALoCoQkUqyZmBEOVWCMaHiQDjx/Iz/ZuSPQaXA7MnP6F+6DSGZfRKbmtKpYSFH1B8NXWnpYLJift X-Received: by 10.194.190.79 with SMTP id go15mr51242828wjc.80.1440530629427; Tue, 25 Aug 2015 12:23:49 -0700 (PDT) Received: from [10.0.0.4] ([109.64.134.34]) by smtp.googlemail.com with ESMTPSA id y13sm284413wjq.26.2015.08.25.12.23.37 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 25 Aug 2015 12:23:48 -0700 (PDT) To: "Zhang, Helin" <helin.zhang@intel.com>, Vlad Zolotarov <vladz@cloudius-systems.com> References: <1439489195-31553-1-git-send-email-vladz@cloudius-systems.com> <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E1AE6@SHSMSX104.ccr.corp.intel.com> <55CD7EA5.6060100@cloudius-systems.com> <6A0DE07E22DDAD4C9103DF62FEBC0909D3E116@shsmsx102.ccr.corp.intel.com> <CAOYyTHaymoNj92+_F1NaP6vPmGO9bdJV7VY7V052RrR_NjRUPw@mail.gmail.com> <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E3E98@SHSMSX104.ccr.corp.intel.com> <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E65FF@SHSMSX104.ccr.corp.intel.com> <CAOYyTHZ062SGrshnpFKnm6yap-GiQRdQ2yaB9-UcOotOXqRYjA@mail.gmail.com> <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E6668@SHSMSX104.ccr.corp.intel.com> <55DCB975.2030000@cloudius-systems.com> <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E66A4@SHSMSX104.ccr.corp.intel.com> From: Avi Kivity <avi@cloudius-systems.com> Message-ID: <55DCC0B8.9000809@cloudius-systems.com> Date: Tue, 25 Aug 2015 22:23:36 +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: <F35DEAC7BCE34641BA9FAC6BCA4A12E70A8E66A4@SHSMSX104.ccr.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" <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 <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Tue, 25 Aug 2015 19:23:49 -0000 On 08/25/2015 10:16 PM, Zhang, Helin wrote: > >> -----Original Message----- >> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com] >> Sent: Tuesday, August 25, 2015 11:53 AM >> To: Zhang, Helin >> Cc: Lu, Wenzhuo; dev@dpdk.org >> Subject: Re: [dpdk-dev] [PATCH v1] ixgbe_pmd: forbid tx_rs_thresh above 1 for >> all NICs but 82598 >> >> >> >> On 08/25/15 21:43, Zhang, Helin wrote: >>> Hi Vlad >>> >>> I think this could possibly be the root cause of your TX hang issue. >>> Please try to limit the number to 8 or less, and then see if the issue >>> will still be there or not? >>> >> Helin, the issue has been seen on x540 devices. Pls., see a chapter >> 7.2.1.1 of x540 devices spec: >> >> A packet (or multiple packets in transmit segmentation) can span any number of >> buffers (and their descriptors) up to a limit of 40 minus WTHRESH minus 2 (see >> Section 7.2.3.3 for Tx Ring details and section Section 7.2.3.5.1 for WTHRESH >> details). For best performance it is recommended to minimize the number of >> buffers as possible. >> >> Could u, pls., clarify why do u think that the maximum number of data buffers is >> limited by 8? > OK, i40e hardware is 8, so I'd assume x540 could have a similar one. Yes, in your case, > the limit could be around 38, right? > Could you help to make sure there is no packet to be transmitted uses more than > 38 descriptors? > I heard that there is a similar hang issue on X710 if using more than 8 descriptors for > a single packet. I am wondering if the issue is similar on x540. > > I believe that the ixgbe Linux driver does not limit packets to 8 fragments, so apparently the hardware is capable.