From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: vhost-switch example: huge memory need and CRC off-loading issue Date: Fri, 7 Aug 2015 19:31:08 +0200 Message-ID: <55C4EB5C.4080001@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit To: dev@dpdk.org Return-path: Received: from thoth.sbs.de (thoth.sbs.de [192.35.17.2]) by dpdk.org (Postfix) with ESMTP id 1353B5682 for ; Fri, 7 Aug 2015 19:31:09 +0200 (CEST) Received: from mail1.siemens.de (mail1.siemens.de [139.23.33.14]) by thoth.sbs.de (8.15.1/8.15.1) with ESMTPS id t77HV9sx015731 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 7 Aug 2015 19:31:09 +0200 Received: from md1f2u6c.ww002.siemens.net ([139.25.68.37]) by mail1.siemens.de (8.15.1/8.15.1) with ESMTP id t77HV9L9018123 for ; Fri, 7 Aug 2015 19:31:09 +0200 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" Hi again, two findings in the vhost-switch example code that can cause grey hair for starters: - MAX_QUEUES of 512 causes pretty high memory need for the application (something between 1 and 2G) - is that really needed? I'm now running with 32, and I'm able to get away with 256M. Can we tune this default? - hw_strip_crc is set to 0, but either the igb driver or the ET2 quad port adapter I'm using is ignoring this. It does strip the CRC, so does software, and I'm losing 4 bytes on each unpadded packet. Known issue? Thanks, Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux