From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.233] helo=mgw-mx06.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1M1w3e-0000Ml-El for linux-mtd@lists.infradead.org; Thu, 07 May 2009 05:22:18 +0000 Subject: Re: Load UBI faster From: Artem Bityutskiy To: simon polette In-Reply-To: <72795ccb0905060026q7dcb45c0u15c35943374fcc78@mail.gmail.com> References: <72795ccb0905060026q7dcb45c0u15c35943374fcc78@mail.gmail.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 07 May 2009 08:22:02 +0300 Message-Id: <1241673722.27549.14.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2009-05-06 at 09:26 +0200, simon polette wrote: > I'm trying to improve boot time on a at91sam9261ek board. I boot on > nand flash with ubifs. It take about 400ms to load ubi and ubifs. > Do you know if fastboot technology, which consist in loading drivers > asynchronously, is conceivable with UBI ? > Thanks for your help. Fastbood is applicable in the situation when initialization is mostly about sleeping and waiting for hw. In case of UBI, it reads from flash and calculates CRC. The reading from NAND is usuall synchronous, so this process takes 100% of your CPU. One way to optimize this a little would be to use on-flash BBT. Usually the nand core scans full NAND to find bad blocks. With on-flash BBT this could be avoided. But probably this would not give you much. How big is your NAND? -- Best regards, Artem Bityutskiy (Битюцкий Артём)