From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <dev-bounces@dpdk.org> Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 24DECA00C4; Fri, 1 Jul 2022 14:24:43 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id BF2734069D; Fri, 1 Jul 2022 14:24:42 +0200 (CEST) Received: from mx0b-0016f401.pphosted.com (mx0a-0016f401.pphosted.com [67.231.148.174]) by mails.dpdk.org (Postfix) with ESMTP id B7E6940150 for <dev@dpdk.org>; Fri, 1 Jul 2022 14:24:40 +0200 (CEST) Received: from pps.filterd (m0045849.ppops.net [127.0.0.1]) by mx0a-0016f401.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2611krjg012686; Fri, 1 Jul 2022 05:24:39 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marvell.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=pfpt0220; bh=I33U+ly91BltLO0ijzpBlstukm8meL8w/vdPI64qT6I=; b=B+vY0MPUaykuV87i92Ejur+tIvian6Ziu/pOoxCht2ibOD1Ui3I4CGicEVjr09JyRwkh 836a9gkL6bNpA5ov6Ueg68ipi+WUFd0SW3J3Ur3kST9lSVSQVy5Xnkjk7re7PbjI7myw mUPzqng25L0/o5KqSWW+5X9A8Oj2E+eh5dI1yugse1OTws6A7xDFs134K4UiTdOqm5Vm IlXGZOpPiQN1MbCZqsq66drx04hx5ds6u7DXyZKdqPiUGqTaLMoPeBcPN4P/QMt9CYao Y7517yDkh2PHEqDvnCjgmQ2Li1gGQGjVJmWC8i6tMuTIUl0wK5T7AQPKJXSnIn1I/wLN cw== Received: from dc5-exch01.marvell.com ([199.233.59.181]) by mx0a-0016f401.pphosted.com (PPS) with ESMTPS id 3h1akbncvg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Fri, 01 Jul 2022 05:24:38 -0700 Received: from DC5-EXCH02.marvell.com (10.69.176.39) by DC5-EXCH01.marvell.com (10.69.176.38) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 1 Jul 2022 05:24:37 -0700 Received: from maili.marvell.com (10.69.176.80) by DC5-EXCH02.marvell.com (10.69.176.39) with Microsoft SMTP Server id 15.0.1497.18 via Frontend Transport; Fri, 1 Jul 2022 05:24:37 -0700 Received: from localhost.localdomain (unknown [10.28.34.29]) by maili.marvell.com (Postfix) with ESMTP id 5796C3F7041; Fri, 1 Jul 2022 05:24:35 -0700 (PDT) From: Shijith Thotton <sthotton@marvell.com> To: <stephen@networkplumber.org> CC: <dev@dpdk.org>, <jerinj@marvell.com>, <olivier.matz@6wind.com>, <sthotton@marvell.com>, <thomas@monjalon.net> Subject: Re: [PATCH] mbuf: add mbuf physical address field to dynamic field Date: Fri, 1 Jul 2022 17:54:34 +0530 Message-ID: <20220701122434.1887783-1-sthotton@marvell.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220630094538.5b27d0c6@hermes.local> References: <20220630094538.5b27d0c6@hermes.local> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: 63yCZcsGhDj0n7bRLo67XNCIxnfgc-Bg X-Proofpoint-ORIG-GUID: 63yCZcsGhDj0n7bRLo67XNCIxnfgc-Bg X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-01_07,2022-06-28_01,2022-06-22_01 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org >> If all devices are configured to run in IOVA mode as VA, physical >> address field of mbuf (buf_iova) won't be used. In such cases, buf_iova >> space is free to use as a dynamic field. So a new dynamic field member >> (dynfield2) is added in mbuf structure to make use of that space. >> >> A new mbuf flag RTE_MBUF_F_DYNFIELD2 is introduced to help identify the >> mbuf that can use dynfield2. >> >> Signed-off-by: Shijith Thotton <sthotton@marvell.com> > > This seems like a complex and potentially error prone way to do this. > What is the use case? > PCI drivers with the flag RTE_PCI_DRV_NEED_IOVA_AS_VA only works in IOVA mode as VA. buf_iova field of mbuf is not used by those PMDs and can be used as a dynamic area to save space. > How much of a performance gain? No change in performance.