Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752723Ab0KXIpT (ORCPT ); Wed, 24 Nov 2010 03:45:19 -0500 Received: from mga11.intel.com ([192.55.52.93]:59843 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752377Ab0KXIpS (ORCPT ); Wed, 24 Nov 2010 03:45:18 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,247,1288594800"; d="scan'208";a="860885098" From: "Dong, Chuanxiao" To: Kyungmin Park CC: "linux-mmc@vger.kernel.org" , "cjb@laptop.org" , "linux-kernel@vger.kernel.org" , "alan@linux.intel.com" , "arjan@linux.intel.com" , "Yuan, Hang" , =?utf-8?B?7KCV7J6s7ZuI?= Date: Wed, 24 Nov 2010 16:44:13 +0800 Subject: RE: [PATCH v1 0/4]mmc: enable eMMC4.41 new feature background operations and HPI Thread-Topic: [PATCH v1 0/4]mmc: enable eMMC4.41 new feature background operations and HPI Thread-Index: AcuLr1FE+V7z7BD9T46qcRB8jn9CiAAAPxSg Message-ID: <5D8008F58939784290FAB48F549751983125B43D44@shsmsx502.ccr.corp.intel.com> References: <20101123084309.GA17754@intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id oAO8jRx4010909 Content-Length: 1410 Lines: 17 > > Basic question. Do you have any performance gain or improvement? > In my test environment. no performance gain. Yes I know it's not for > performance improvement. My understanding: If BKOPS feature is not enabled, the background operations will be started when card handles some read or write command. This will impact read/write performance. If BKOPS is enabled, driver can check whether need to do a BKOPS each time after card handled a read/write command. If need, driver can start BKOPS as soon as possible when user request is empty. This will can improve read/write performance. So I think, anyhow background operations can improve the performance, but only can be seen when your test card need to do a background operations. If your card needn't, there will be no performance gain I think. Driver will works as normal. BTW, the BKOPS is an operational features for eMMC4.41 card, to ensure whether the card support this feature, check ext_csd[502]. > > How to measure or check it has some improvement? > Any ideas? > Right now I didn't know how to do a precise measurement. Maybe keep on transferring large data for a long time with a card which enabled/or not the BKOPS feature can help to get some measurement data. Thanks Chuanxiao ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?