From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 8A3BEA0546; Wed, 7 Apr 2021 10:43:42 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 128161410AB; Wed, 7 Apr 2021 10:43:42 +0200 (CEST) Received: from new2-smtp.messagingengine.com (new2-smtp.messagingengine.com [66.111.4.224]) by mails.dpdk.org (Postfix) with ESMTP id DD5B1407FF for ; Wed, 7 Apr 2021 10:43:40 +0200 (CEST) Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailnew.nyi.internal (Postfix) with ESMTP id 1EF125808E4; Wed, 7 Apr 2021 04:43:40 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute2.internal (MEProxy); Wed, 07 Apr 2021 04:43:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=monjalon.net; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:content-type; s=fm3; bh= YCtEas5+Fzewc3LmNNCnQYxLSvlpXac3+i9JiSAikNw=; b=BDpQ4vBGUpJcv7+/ IRd80cPCHfFoyHPm3U4sPxJMMI3po18eYjlT4MjX4jY//rRhjBw5vyn4mJrbYeWs O4spoR1Y5Nrj41NyXJMMGwWVsJ+7M7EmV8s4Ljxe8Rc4dxxz2xx+YjBCcT4aYZcV 2A1HJKLig8F3a6uDa1RXtIn0FlxwWzuiv52FkQMlQemLIfKXJAV6/rSTbxVK/U2r pR1D/84s0OP7tinqTCMjk8aworvhvZfUlSNSwCTpGMRIbv2pQ8fPN5btkuLHVkEi sJOEY+4rqtsyUVkZ2JmghtXXgQmuGYjnUAI/+LeDPYxkxV3R9svsTH9tfmSVNM+I /D2kEA== 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-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; bh=YCtEas5+Fzewc3LmNNCnQYxLSvlpXac3+i9JiSAik Nw=; b=mcleRSu0lsXYUkxguA6G5P9hVkC37FVfTtfFnf6KsjgYGRGiHN+U/hUZJ zxtRfB4s7iqVuBvn+p1BVhReidqlYp2nGcFIR0JV4t1gW+qdZ/IQ2XIg7gF4pppu JXqfwhKZ87RoJBtuSlhMWEDEXGws0l2Lv2dZ+eTLbP2GpejsBUW7MgMQb97pGGJR 2cn/wyIp5BN38VkGnL28uT6YFQmZtaHkC0OERwLJlfFfrQajpVWYYMlp7XiSoY7+ Qf3fDcLO+1x7TzdYAczshnDAa24DdVfTul3Cg7Qb42za3cCndZ/2uTvHCRNz+Ene XKrBhrTlpf47lED/gOnS7hHaORPBQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrudejjedgtdejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkfgjfhgggfgtsehtufertddttddvnecuhfhrohhmpefvhhhomhgr shcuofhonhhjrghlohhnuceothhhohhmrghssehmohhnjhgrlhhonhdrnhgvtheqnecugg ftrfgrthhtvghrnhepudeggfdvfeduffdtfeeglefghfeukefgfffhueejtdetuedtjeeu ieeivdffgeehnecukfhppeejjedrudefgedrvddtfedrudekgeenucevlhhushhtvghruf hiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehthhhomhgrshesmhhonhhjrghl ohhnrdhnvght X-ME-Proxy: Received: from xps.localnet (184.203.134.77.rev.sfr.net [77.134.203.184]) by mail.messagingengine.com (Postfix) with ESMTPA id 3C8291080057; Wed, 7 Apr 2021 04:43:37 -0400 (EDT) From: Thomas Monjalon To: Maxime Coquelin , bruce.richardson@intel.com, jerinj@marvell.com, andrew.rybchenko@oktetlabs.ru, hemant.agrawal@nxp.com, nipun.gupta@nxp.com, g.singh@nxp.com, radhac@marvell.com, vburru@marvell.com Cc: Cheng Jiang , dev@dpdk.org, chenbo.xia@intel.com, dev@dpdk.org, jiayu.hu@intel.com, yvonnex.yang@intel.com, yinan.wang@intel.com, alexr@nvidia.com, shahafs@nvidia.com Date: Wed, 07 Apr 2021 10:43:36 +0200 Message-ID: <1700633.VhrhA6iQC3@thomas> In-Reply-To: <2267082.chWHW8dCnR@thomas> References: <20210317054054.34616-1-Cheng1.jiang@intel.com> <23c4f6e7-4895-44b7-4ff0-3a02f9f3f86a@redhat.com> <2267082.chWHW8dCnR@thomas> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH] examples/vhost: fix ioat ring space in callbacks X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" +Cc more people to start a discussion about a potential DMA API. If you think it is interesting, we can start a fresh discussion thread. 07/04/2021 10:26, Thomas Monjalon: > 07/04/2021 09:47, Maxime Coquelin: > > > > On 3/17/21 6:40 AM, Cheng Jiang wrote: > > > We use ioat ring space for determining if ioat callbacks can enqueue a > > > packet to ioat device. But there is one slot can't be used in ioat > > > ring due to the ioat driver design, so we need to reduce one slot in > > > ioat ring to prevent ring size mismatch in ioat callbacks. [...] > > > --- a/examples/vhost/ioat.c > > > +++ b/examples/vhost/ioat.c > > > @@ -113,7 +113,7 @@ open_ioat(const char *value) > > > goto out; > > > } > > > rte_rawdev_start(dev_id); > > > - cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE; > > > + cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE - 1; > > > > That really comforts me in thinking we need a generic abstraction for > > DMA devices. How is the application developer supposed to know that > > the DMA driver has such weird limitations? > > Having a generic DMA API may be interesting. > Do you know any other HW candidate for such an API? > Do you think rte_memcpy can be used as a SW driver?