From mboxrd@z Thu Jan  1 00:00:00 1970
From: js@sig21.net (Johannes Stezenbach)
Date: Wed, 27 Feb 2013 11:20:53 +0100
Subject: [RFC PATCH v2 0/4] Add support for LZ4-compressed kernel
In-Reply-To: <20130227095139.GX17833@n2100.arm.linux.org.uk>
References: <1361859870-15751-1-git-send-email-kyungsik.lee@lge.com>
 <512D1C12.4080109@oberhumer.com> <20130227073646.GA22333@Corona>
 <20130227095139.GX17833@n2100.arm.linux.org.uk>
Message-ID: <20130227102053.GA24274@sig21.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Feb 27, 2013 at 09:51:39AM +0000, Russell King - ARM Linux wrote:
> On Wed, Feb 27, 2013 at 04:36:47PM +0900, Kyungsik Lee wrote:
> > Compiler: Linaro ARM gcc 4.6.2
> > 2. ARMv7, 1.7GHz based board
> >    Kernel: linux 3.7
> >    Uncompressed Kernel Size: 14MB
> >          Compressed Size  Decompression Speed
> >     LZO  6.0MB            34.1MB/s            Old
> >          ----------------------------------------
> >          6.0MB            34.7MB/s            New
> >          6.0MB            52.2MB/s(UA)
> >     =============================================
> >     LZ4  6.5MB            86.7MB/s
> > UA: Unaligned memory Access support
> 
> That is pretty conclusive - it shows an 8% increase in image size vs a
> 66% increase in decompression speed.  It will take a _lot_ to offset
> that increase in decompression speed.
> 
> So, what I think is that yes, we should accept LZ4 and drop LZO from
> the kernel - the "fast but may not be small" compression title has
> clearly been taken by LZ4.

I think LZO may be used by squashfs, jffs2 and btrfs, thus you
cannot drop it without breaking on disk storage formats.

Johannes