From mboxrd@z Thu Jan 1 00:00:00 1970 From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=) Date: Thu, 18 Nov 2010 09:15:28 +0100 Subject: [PATCH] ARM: add support for uncompressed uImage kernel In-Reply-To: <201011180838.26679.alexander.stein@systec-electronic.com> References: <1289310656-29502-1-git-send-email-alexander.stein@systec-electronic.com> <20101109140455.GA6680@n2100.arm.linux.org.uk> <201011180838.26679.alexander.stein@systec-electronic.com> Message-ID: <20101118081528.GI8942@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Nov 18, 2010 at 08:38:26AM +0100, Alexander Stein wrote: > Soory for late answer, > > On Saturday 13 November 2010, 11:47:41 Albin Tonnerre wrote: > > wrote: > > > Is it really faster to copy an uncompressed image than it is to > > > decompress using LZMA with caches on? > > > > In my experience, using LZMA is painfully slow on older ARM CPUs. > > > > If you really need to boot quickly you might want to try LZO, which > > should give you results close to the uncompressed performance. It > > might still be slower though, especially if you're able to load your > > kernel image to memory fairly quickly > > We only have experience with GZIP. Our compressed kernel is ~1,8MB and > uncompressed ~4MB. > On an AT91 ARM9 SoC the decompression takes about 1-2s of time. Caches should > be disabled, as far as I could see in decompression code. Caches are enabled in line 248 of http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/arm/boot/compressed/head.S;h=6825c34646d4e02f24b0eefe7ab4e012bca05208;hb=HEAD Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |