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Date: Wed, 27 Feb 2013 09:51:39 +0000
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Kyungsik Lee <kyungsik.lee@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
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        Richard Cochran <richardcochran@gmail.com>,
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        Egon Alter <egon.alter@gmx.net>, hyojun.im@lge.com, chan.jeong@lge.com,
        raphael.andy.lee@gmail.com
Subject: Re: [RFC PATCH v2 0/4] Add support for LZ4-compressed kernel
Message-ID: <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>
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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.

Akpm - what's your thoughts?