From mboxrd@z Thu Jan 1 00:00:00 1970 From: "shesha Sreenivasamurthy (shesha)" Subject: Reshuffling of rte_mbuf structure. Date: Sat, 31 Oct 2015 04:44:10 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: "dev@dpdk.org" 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) 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 Content-Language: en-US List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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; }