From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from risingsoftware01.propagation.net ([66.221.33.65]) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1JofFU-00008H-H6 for linux-mtd@lists.infradead.org; Wed, 23 Apr 2008 13:43:00 +0000 Date: Wed, 23 Apr 2008 23:42:54 +1000 From: Hamish Moffatt To: Artem Bityutskiy Subject: Re: [RFC] slight UBI scan time improvement Message-ID: <20080423134254.GA17867@cloud.net.au> References: <1208882552.11721.13.camel@sauron> <20080423073840.GA9472@cloud.net.au> <480EEFAB.7010304@parrot.com> <1208938864.11721.44.camel@sauron> <20080423124046.GA16201@cloud.net.au> <1208955467.11721.69.camel@sauron> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1208955467.11721.69.camel@sauron> Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Apr 23, 2008 at 03:57:47PM +0300, Artem Bityutskiy wrote: > On Wed, 2008-04-23 at 22:40 +1000, Hamish Moffatt wrote: > > Well I think from past use of "time ubiattach ..." that most of > > the missing time is in the attach. > Sure, UBI takes most of the time. Its just if you want to save 1.2+ sec, > you may try to play with on-flash BBT. I'm not sure what this means.. ? Instead of having to scan each block to check the marker, it has a central table? And that table is created once by an initial scan and then added to when UBI declares a block bad? How do I access this feature? > > What sort of speed do you get using > > dd if=/dev/mtdblock9 of=/tmp/foo bs=128K count=64 > > (where mtdblock9 is your raw mtd NAND device). I'm seeing about 6 > > seconds to read that 8Mb, which is quite long I guess. > I have busybox so stuff like 128K does not work. Here are my results: Hmm I have busybox (1.9.x) also, 128K works ok for me. > # time dd if=/dev/mtd4 of=/dev/null bs=131072 count=64 > 64+0 records in > 64+0 records out > real 0m 0.28s > user 0m 0.00s > sys 0m 0.28s Very good. It's about 6.1 seconds for me :-( (Worse on my previous hardware which had compact flash on IDE without a hardware IDE controller: over 11 seconds.) Hamish -- Hamish Moffatt VK3SB