From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id C34F9A04E7; Sun, 1 Nov 2020 17:13:00 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 6AEB02BFE; Sun, 1 Nov 2020 17:12:59 +0100 (CET) Received: from wnew2-smtp.messagingengine.com (wnew2-smtp.messagingengine.com [64.147.123.27]) by dpdk.org (Postfix) with ESMTP id C05732BF7 for ; Sun, 1 Nov 2020 17:12:56 +0100 (CET) Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailnew.west.internal (Postfix) with ESMTP id CAFDF5FE; Sun, 1 Nov 2020 11:12:54 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute2.internal (MEProxy); Sun, 01 Nov 2020 11:12:55 -0500 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=fm2; bh= T9SyXBOI85B/+hNm9WtIvV7dne/uBvqjudKdE/khtJ8=; b=RWSXU2EWd9kjSlUk tkyrXKgtxiLOzDvPV+u1tvT5qvW0kHepzX7Sxx/jZzfCc/amX70Ks8TnFezhVhHe jgliHA5nFPcJIxO6pxCcMo5hWX8WUKf3Zkh8W9tvwz9nJloQXQCD6sLxACyQGu4I qTFlffCUxmaktSAK9W1VJYGmROqzj2bWjjtEk8IKRqnK1UGHXJCbHJYnp2yisXLg KymoLWumItgWCMJDPbSYqdfYYOhhOFMFYZM6uS7dzoDQXfQaQFy/VHM+JWSvrwmr 3pj6USi+BqKEox6293UxilbmDAoNZxGy1IrN3YlwVd7UQ4GjCMwGOO7MQOe0a6eG b3DZSQ== 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=fm1; bh=T9SyXBOI85B/+hNm9WtIvV7dne/uBvqjudKdE/kht J8=; b=HvBgNc6MQdZqpaIq2/284pIipWcIMoCSSu/HjuNvpxpDIrkXSp94k6lhR dHy1anvEbS+TsjLJpVFnBa3XG2/nINTidzk7iJAcRE10mn5C8fL1gidSj2g3g1kD ht0jIx5aBBHh/Pn3+uhMyj6gYSGYNgG+dMnkxsroxNunfUS95cIcft09Y955DMkf OKogXBYKjzZWcYvQ+HACeA0Sv69hmOikAPXSdlN7px1fpSYC6V53ZOzw7w1tENBX PYODCpmx4z6VVNHWLyGyg+GAIH3GtDBZhns5qlBgaivNqYTWlUkqUFgPGWXdQVIn hpfuW0sbpZjtdboTNn74Nr7AEClkQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrleelgdekkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefhvffufffkjghfggfgtgesthfuredttddtvdenucfhrhhomhepvfhhohhmrghs ucfoohhnjhgrlhhonhcuoehthhhomhgrshesmhhonhhjrghlohhnrdhnvghtqeenucggtf frrghtthgvrhhnpedugefgvdefudfftdefgeelgffhueekgfffhfeujedtteeutdejueei iedvffegheenucfkphepjeejrddufeegrddvtdefrddukeegnecuvehluhhsthgvrhfuih iivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepthhhohhmrghssehmohhnjhgrlhho nhdrnhgvth 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 14AB83064686; Sun, 1 Nov 2020 11:12:51 -0500 (EST) From: Thomas Monjalon To: Slava Ovsiienko , Andrew Rybchenko , "jerinj@marvell.com" Cc: dev@dpdk.org, "dev@dpdk.org" , "ferruh.yigit@intel.com" , "david.marchand@redhat.com" , "bruce.richardson@intel.com" , "olivier.matz@6wind.com" , Nithin Dabilpuram , Kiran Kumar K , Ray Kinsella , Neil Horman , Jerin Jacob Date: Sun, 01 Nov 2020 17:12:50 +0100 Message-ID: <2042160.LKydRhkSHl@thomas> In-Reply-To: References: <20201029092751.3837177-1-thomas@monjalon.net> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH 10/15] net/octeontx2: switch timestamp to dynamic mbuf field 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: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 30/10/2020 13:41, Jerin Jacob: > On Thu, Oct 29, 2020 at 5:22 PM Slava Ovsiienko wrote: > > From: Andrew Rybchenko > > > > Just five cents - exporting the offset (making it global) might have side effect impacting the performance. > > I agree with Slava. The offset value should be stored in the PMD structure. > IMO, We can have an ethdev API to get the offset and store it in PMD's > fastpath structures in the slow path > to use in fastpath. > > > Offset might be located in some memory sharing the cacheline with some other variables. > > If these variables are writable and are being updated frequently - we might get the cache contention. > > I'd prefer to keep all dynamic offsets In the PMD and entirely control memory allocation > > attributes for these ones. Hence, exporting is OK, but practical usage in datapath is questionable. Yes this is a major design point: the field offsets are preferably stored in a hot cache line which depends on the driver, library or application context.