From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.230] helo=mgw-mx03.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1MTEF1-0002Mt-6M for linux-mtd@lists.infradead.org; Tue, 21 Jul 2009 12:14:47 +0000 Subject: Re: [PATCH] UBI: Decrease I/O count in ubi_scan From: Artem Bityutskiy To: Corentin Chary In-Reply-To: <1248175591-4592-1-git-send-email-corentincj@iksaif.net> References: <1248175591-4592-1-git-send-email-corentincj@iksaif.net> Content-Type: text/plain; charset="UTF-8" Date: Tue, 21 Jul 2009 15:14:11 +0300 Message-Id: <1248178451.24676.9.camel@localhost> 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, 2009-07-21 at 13:26 +0200, Corentin Chary wrote: > Merge ec_hdr and vid_hdr read in one ubi_io_read() > This result in a 25% speedup with nandsim, and 6% > speedup on an AT91SAM9263 board with a 200Mo UBI volume. > > Signed-off-by: Corentin Chary > --- > drivers/mtd/ubi/io.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++- > drivers/mtd/ubi/scan.c | 35 +++++++++++++------------ > drivers/mtd/ubi/ubi.h | 4 +++ > 3 files changed, 87 insertions(+), 19 deletions(-) Yeah, I did the same optimization some time ago: http://lists.infradead.org/pipermail/linux-mtd/2008-April/021311.html Could you please take a look at those patches as well, and if they are any better, use them or improve yours. I do not remember the details, to be frank. No one reported a significant improvement, so I dropped it. nandsim improvement is not very interesting, but the AT91SAM9263 is. Which flash is there? And why do you presume is the improvement - just less calls to MTD or really less I/O? Note MTD usually caches the last read NAND page, so usually this is not about less I/O. -- Best Regards, Artem Bityutskiy (Артём Битюцкий)