From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f66.google.com (mail-it0-f66.google.com [209.85.214.66]) by dpdk.org (Postfix) with ESMTP id 6095D5580 for ; Sat, 23 Jul 2016 11:02:34 +0200 (CEST) Received: by mail-it0-f66.google.com with SMTP id j124so4517218ith.3 for ; Sat, 23 Jul 2016 02:02:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=rwr2DYDozkBKuus0Gsc4/6/bDN4Fuo0IMRAUNMbkoiQ=; b=hjlxE0PcYLouQeNRwiTs7et56RlhwtzMmKPlyfZS36H+cC157HTKzzddigt+ldAty/ rkP6Pdtfzu4cPzgzEbSQ/HPtargLfGaa4JIFbR1WHzbUiRoAZ1aP/XLiB9Q03wnP9n8G jgTmC/m6XfEuXbGa8AFMl1M7OuV0RCOp6NvpDej+LZrNP2uiApa7D4dteN09i5ghdcSg ZpnPUkkRKYFb4oETMlLfzJDRU6bWpAUtrV9sg9smK2xM3eYE5zIrAkf365JhwajSG/9a pL9WWoXjs2+VlKYRy0tSC0atM7ShiqP8AE4moFzxn81ZtCGZ6SXYsFcWjMR3Jr6qAVG+ +Dbg== 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:from:date :message-id:subject:to:cc; bh=rwr2DYDozkBKuus0Gsc4/6/bDN4Fuo0IMRAUNMbkoiQ=; b=cVEeqaoATjX1gS7tflkSdmVDiINhB7hTHaunCO8sfHOrGkFKbnDNTMUD6C0fepL5zJ 7eynBKoI2LNk/hqq6RYY+SECLST+NIrDxY9Q9QsU5otbVdOhiqTHkwn3j/89aBcP4iSK MkDd75f/J004uYWMOaE8tddfawQTD9kB5q1iBAnH6dHdLhyILuHjEuniQGmAN9RbsA0o T7AUuYQJNi8y9uHou6brPUu4+TxWgOU5U2kST4ky4wJh72UA8nymlHsoTpd9B/euyvSD DlvRQa796Ojqlq/fAZTGIrH8GUastAXqQbHw0FsTYzv6mJ0yodDYmshRQKqPpqQssajH sMvg== X-Gm-Message-State: AEkooutXiu1YRKhW5As6F4jwQVmS6DnA0BhUlpOQZuPyGmssF20cObzJTOBEwuO20Nms+afdasJUQBQVEW9u7J0C X-Received: by 10.36.46.136 with SMTP id i130mr8825289ita.62.1469264553694; Sat, 23 Jul 2016 02:02:33 -0700 (PDT) MIME-Version: 1.0 Received: by 10.36.193.66 with HTTP; Sat, 23 Jul 2016 02:02:33 -0700 (PDT) In-Reply-To: <20160723060515.GA13747@localhost.localdomain> References: <20160715043951.32040-1-juhamatti.kuusisaari@coriant.com> <2601191342CEEE43887BDE71AB97725836B7E32F@irsmsx105.ger.corp.intel.com> <14017551.U6D1dIIx0P@xps13> <20160723060515.GA13747@localhost.localdomain> From: Thomas Monjalon Date: Sat, 23 Jul 2016 11:02:33 +0200 Message-ID: To: Jerin Jacob Cc: Juhamatti Kuusisaari , "dev@dpdk.org" , "Ananyev, Konstantin" Content-Type: text/plain; charset=UTF-8 Subject: Re: [dpdk-dev] [PATCH] lib: change rte_ring dequeue to guarantee ordering before tail update 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: Sat, 23 Jul 2016 09:02:34 -0000 2016-07-23 8:05 GMT+02:00 Jerin Jacob : > On Thu, Jul 21, 2016 at 11:26:50PM +0200, Thomas Monjalon wrote: >> > > Consumer queue dequeuing must be guaranteed to be done fully before the tail is updated. This is not guaranteed with a read barrier, >> > > changed to a write barrier just before tail update which in practice guarantees correct order of reads and writes. >> > > >> > > Signed-off-by: Juhamatti Kuusisaari >> > >> > Acked-by: Konstantin Ananyev >> >> Applied, thanks > > There was ongoing discussion on this > http://dpdk.org/ml/archives/dev/2016-July/044168.html Sorry Jerin, I forgot this email. The problem is that nobody replied to your email and you did not nack the v2 of this patch. > This change may not be required as it has the performance impact. We need to clearly understand what is the performance impact (numbers and use cases) on one hand, and is there a real bug fixed by this patch on the other hand? Please guys make things clear and we'll revert if needed.