From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-fx0-f222.google.com ([209.85.220.222]) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1NTlFZ-0006oR-7k for linux-mtd@lists.infradead.org; Sun, 10 Jan 2010 00:01:49 +0000 Received: by fxm22 with SMTP id 22so22937114fxm.2 for ; Sat, 09 Jan 2010 16:01:44 -0800 (PST) Subject: Re: ubiattach taking very long time From: Artem Bityutskiy To: twebb In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Sun, 10 Jan 2010 02:01:41 +0200 Message-Id: <1263081701.7315.128.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2009-12-22 at 09:14 -0500, twebb wrote: > Does it make any sense that a ubiattach would take > 20 secs? The > flash I'm using is Samsung 4GiB MLC NAND flash. I'm running 2.6.28 > kernel. Here's the capture... Yes, it can do this. UBI is not scalable, read here: http://www.linux-mtd.infradead.org/doc/ubi.html#L_scalability Please, also take a look here: http://www.linux-mtd.infradead.org/faq/ubi.html#L_attach_faster To really fix your problem we need UBI2. In your case, it needs to read 8KiB from each PEB. If you know your I/O speed, you can do the math. To measure your read speed and scan speed, you can use 'mtd_speedtest': http://www.linux-mtd.infradead.org/doc/general.html#L_mtd_tests -- Best Regards, Artem Bityutskiy (Артём Битюцкий)