From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rcdn-iport-1.cisco.com (rcdn-iport-1.cisco.com [173.37.86.72]) by dpdk.org (Postfix) with ESMTP id 577085A4F for ; Sat, 31 Oct 2015 05:44:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=3037; q=dns/txt; s=iport; t=1446266679; x=1447476279; h=from:to:subject:date:message-id:mime-version; bh=bHl7YOI2Quc4NKrGJ9/5WAlMKYFNDvuBtWf4Z7rSVbk=; b=fzKBKSF4FhTlU1Ub96gCPuGFe+WZ+4X29SYEUHDLtXuNuE+aXkKmGUhQ GkVNWt4QPey3+WEz1o9sdPZr+CDqxue/uv6RrnEFZtnUW2CF7wG8noy2T 5xyq1fIxlEyQKtCnv3NuzES1aidxuNQctXS9xMi6K3hYhy89ezzEeyV4K 4=; X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0AIAgBsRjRW/5FdJa1egm5NgUi/LQENgVqHTjgUAQEBAQEBAX8LhDwnZAEMdCcEiEOiUaEQAQEIAiGLdYlABY1UiG8Be4wpgVmEP4kPjRIBHwEBQoQEhWmBBwEBAQ X-IronPort-AV: E=Sophos;i="5.20,221,1444694400"; d="scan'208,217";a="46401789" Received: from rcdn-core-9.cisco.com ([173.37.93.145]) by rcdn-iport-1.cisco.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 31 Oct 2015 04:44:37 +0000 Received: from XCH-RCD-001.cisco.com (xch-rcd-001.cisco.com [173.37.102.11]) by rcdn-core-9.cisco.com (8.14.5/8.14.5) with ESMTP id t9V4ibmp009081 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL) for ; Sat, 31 Oct 2015 04:44:37 GMT Received: from xch-rcd-004.cisco.com (173.37.102.14) by XCH-RCD-001.cisco.com (173.37.102.11) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Fri, 30 Oct 2015 23:44:10 -0500 Received: from xch-rcd-004.cisco.com ([173.37.102.14]) by XCH-RCD-004.cisco.com ([173.37.102.14]) with mapi id 15.00.1104.000; Fri, 30 Oct 2015 23:44:10 -0500 From: "shesha Sreenivasamurthy (shesha)" To: "dev@dpdk.org" Thread-Topic: Reshuffling of rte_mbuf structure. Thread-Index: AQHRE5bISS1IQdF67k2r5hvr+GvFxA== Date: Sat, 31 Oct 2015 04:44:10 +0000 Message-ID: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.24.210.167] MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: [dpdk-dev] Reshuffling of rte_mbuf structure. 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: Sat, 31 Oct 2015 04:44:38 -0000 In Cisco, we are using DPDK for a very high speed packet processor applicat= ion. We don't use NIC TCP offload / RSS hashing. Putting those fields in th= e first cache-line - and the obligatory mb->next datum in the second cache = line - causes significant LSU pressure and performance degradation. If it d= oes not affect other applications, I would like to propose reshuffling of f= ields so that the obligator "next" field falls in first cache line and RSS = hashing goes to next. If this re-shuffling indeed hurts other applications,= another idea is to make it compile time configurable. Please provide feedb= ack. -- - Thanks char * (*shesha) (uint64_t cache, uint8_t F00D) { return 0x0000C0DE; }