From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by dpdk.org (Postfix) with ESMTP id 986EA235 for ; Sat, 8 Jul 2017 18:08:58 +0200 (CEST) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 36969206A1; Sat, 8 Jul 2017 12:08:58 -0400 (EDT) Received: from frontend1 ([10.202.2.160]) by compute1.internal (MEProxy); Sat, 08 Jul 2017 12:08:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=monjalon.net; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-sender :x-me-sender:x-sasl-enc:x-sasl-enc; s=mesmtp; bh=ZVIygMmLWz8czKn 2p+jHKiP4jEk7UC1WBuQTa1Nf8U8=; b=AkV2M58bAcs+foaLy94XooeHmdOBbqZ Gfh4yOk5L2M65hbxr3FNpjCpyCfYTCig/Q6tncSAzZRtdGUKDxr40SXxdonvPaF+ WYdBRg2DmgpsLMEj4NoOR2IPyPIavBhzjnLqtdED8yLE83bfAyqAwz+6zBmGCsGK aqmVM/rxK1Mc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-sender:x-me-sender:x-sasl-enc:x-sasl-enc; s= fm1; bh=ZVIygMmLWz8czKn2p+jHKiP4jEk7UC1WBuQTa1Nf8U8=; b=O238EdBA f982FgIEgFS5kGql4ABy5eUmIaVrwkInPidKvaMgMRo8IEonIF0atWZX9ExejCz4 JgHJof4CZEXN6Uod42L/NsHx7g1weNdeqyGLOk6+Y3wYepEelOdW+WWMTPCrzkXt sNrM/9eOUNACX5ERRy0Y1zsn6JCAhnX+UTL2w3zauJAZBPEDndQsUA87yijd8i+D IyOwaBi+qpQw59003f95XUXZ7tx1WeSCnF58KAdFjyMhHPIj+O9kRVA0YApYysOS Pn9EfCttSazH12DWOZI/YBSOvpO2/XXqokyImQMPJp8fNMjfjbC5s156UNUWZbPk Wpw4Bu7fkfdwWA== X-ME-Sender: X-Sasl-enc: 2Cpzwv7PT92F+YBs7C38WRsBAL1RCubRic9eawWgBm7d 1499530137 Received: from xps.localnet (184.203.134.77.rev.sfr.net [77.134.203.184]) by mail.messagingengine.com (Postfix) with ESMTPA id E316F7E881; Sat, 8 Jul 2017 12:08:57 -0400 (EDT) From: Thomas Monjalon To: Jerin Jacob Cc: dev@dpdk.org, ferruh.yigit@intel.com, john.mcnamara@intel.com Date: Sat, 08 Jul 2017 18:08:57 +0200 Message-ID: <187460180.BTNh70yjrI@xps> In-Reply-To: <20170706062120.3895-1-jerin.jacob@caviumnetworks.com> References: <20170421122223.24194-1-jerin.jacob@caviumnetworks.com> <20170706062120.3895-1-jerin.jacob@caviumnetworks.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH v2] ethdev: introduce lock-free txq capability flag X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 08 Jul 2017 16:08:59 -0000 Hi Jerin, Thanks for the update. I think we can add this new flag in 17.08. I prefer waiting John's review, especially for doc wording, before applying it. I consider it does not hurt to add it post-rc1. See below for my first comment on the doc. 06/07/2017 08:21, Jerin Jacob: > Introducing the DEV_TX_OFFLOAD_MT_LOCKFREE TX capability flag. > if a PMD advertises DEV_TX_OFFLOAD_MT_LOCKFREE capable, multiple threads > can invoke rte_eth_tx_burst() concurrently on the same tx queue without > SW lock. This PMD feature will be useful in the following use cases and > found in the OCTEON family of NPUs. > > 1) Remove explicit spinlock in some applications where lcores > to TX queues are not mapped 1:1. > example: OVS has such instance > https://github.com/openvswitch/ovs/blob/master/lib/netdev-dpdk.c#L299 > https://github.com/openvswitch/ovs/blob/master/lib/netdev-dpdk.c#L1859 > See the the usage of tx_lock spinlock. > > 2) In the eventdev use case, Avoid dedicating a separate TX core for > transmitting and thus enables more scaling as all workers can > send the packets. > > v2: > - Changed the flag name to DEV_TX_OFFLOAD_MT_LOCKFREE(Thomas) > - Updated the documentation in doc/guides/prog_guide/poll_mode_drv.rst > and rte_eth_tx_burst() doxgen comments(Thomas) > > Signed-off-by: Jerin Jacob > --- [...] > +If the PMD is ``DEV_TX_OFFLOAD_MT_LOCKFREE`` capable, multiple threads can invoke ``rte_eth_tx_burst()`` > +concurrently on the same tx queue without SW lock.This PMD feature found in some NICs and A space is missing after the dot. Note: my preference is to start next sentence on a new line (in RST source). > +useful in the following use cases if PMD supports it. See `Hardware Offload`_ for details. This sentence is confusing. I would remove "if PMD supports it". After "following use cases", should we add a colon? The relation with `Hardware Offload`_ is not obvious. > +* Remove explicit spinlock in some applications where lcores to TX queues are not mapped 1:1. Can we reword "lcores to TX queues"? I suggest "lcores are not mapped to Tx queues with 1:1 relation". > +* In the eventdev use case, Avoid dedicating a separate TX core for transmitting and thus Uppercase in the middle of the sentence spotted. > + enables more scaling as all workers can send the packets.