From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([131.228.20.171] helo=mgw-ext12.nokia.com) by canuck.infradead.org with esmtps (Exim 4.63 #1 (Red Hat Linux)) id 1IW9VM-0002vu-PE for linux-mtd@lists.infradead.org; Fri, 14 Sep 2007 07:38:39 -0400 Subject: Re: Increasing read request size in JFFS2 From: Artem Bityutskiy To: payagond@aol.com In-Reply-To: <8C9C4D8EE8B6B02-F08-232@webmail-mf13.sysops.aol.com> References: <8C9C4D8EE8B6B02-F08-232@webmail-mf13.sysops.aol.com> Content-Type: text/plain; charset=utf-8 Date: Fri, 14 Sep 2007 14:38:27 +0300 Message-Id: <1189769907.14370.140.camel@sauron> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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 Fri, 2007-09-14 at 07:24 -0400, payagond@aol.com wrote: > Hi, > I want to know, whether, we can exploit the fast sequential read=20 > (multiple pages at one go) feature of a nand flash device by existing=20 > JFFS2 code. > read_pages in readahead decides to call either=20 > mapping->a_ops->readpages or mapping->a_ops->readpage > can I implement jffs2_readpages to do so? > The problem I feel is (if I have understood correctly) > To read more pages at one shot, we need to anyway read the=20 > jffs2_raw_inode header first and then calculate the lenth to read, will=20 > it give me more performance than what is existing? > regards > payagond JFFS2 reads maximum 3 2K NAND pages at a time, although very rarely. Mostly it reads one page if compression is enabled. --=20 Best regards, Artem Bityutskiy (=D0=91=D0=B8=D1=82=D1=8E=D1=86=D0=BA=D0=B8=D0=B9 =D0=90= =D1=80=D1=82=D1=91=D0=BC)