From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id E250B3798 for ; Thu, 28 Apr 2016 08:16:57 +0200 (CEST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP; 27 Apr 2016 23:16:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,545,1455004800"; d="scan'208";a="693555808" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.162]) by FMSMGA003.fm.intel.com with ESMTP; 27 Apr 2016 23:16:55 -0700 Date: Wed, 27 Apr 2016 23:19:31 -0700 From: Yuanhan Liu To: Huawei Xie Cc: dev@dpdk.org, stephen@networkplumber.org, mukawa@igel.co.jp, kevin.traynor@intel.com, jianfeng.tan@intel.com Message-ID: <20160428061931.GH25677@yliu-dev.sh.intel.com> References: <1461259092-9309-1-git-send-email-huawei.xie@intel.com> <1461747238-124446-1-git-send-email-huawei.xie@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1461747238-124446-1-git-send-email-huawei.xie@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [PATCH] virtio: avoid avail ring entry index update if equal 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, 28 Apr 2016 06:16:58 -0000 On Wed, Apr 27, 2016 at 04:53:58AM -0400, Huawei Xie wrote: > Avail ring is updated by the frontend and consumed by the backend. > There are frequent core to core cache transfers for the avail ring. > > This optmization avoids avail ring entry index update if the entry > already holds the same value. > As DPDK virtio PMD implements FIFO free descriptor list (also for > performance reason of CACHE), in which descriptors are allocated > from the head and freed to the tail, with this patch in most cases > avail ring will remain the same, then it would be valid in both caches > of frontend and backend. Acked-by: Yuanhan Liu > > Signed-off-by: Huawei Xie > Suggested-by: ms >> Michael S. Tsirkin And applied to dpdk-next-virtio, with few tiny changes: - we normally put suggested/reported-by above the SoB. - removed "ms >>" Thanks. --yliu