From: kyungsik.lee@lge•com (kyungsik.lee)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH 0/4] Add support for LZ4-compressed kernels
Date: Fri, 01 Feb 2013 16:00:57 +0900 [thread overview]
Message-ID: <510B6829.7050908@lge.com> (raw)
In-Reply-To: <254788880.18003.1359493798737.JavaMail.tomcat@be12>
On 2013-01-30 ?? 6:09, Rajesh Pawar wrote:
>> Andrew Morton <akpm@linux-foundation•org> wrote:
>>
>> On Sat, 26 Jan 2013 14:50:43 +0900
>> Kyungsik Lee <kyungsik.lee@lge•com> wrote:
>>> This patchset is for supporting LZ4 compressed kernel and initial ramdisk on
>>> the x86 and ARM architectures.
>>>
>>> According to [[http://code.google.com/p/lz4/,]] LZ4 is a very fast lossless
>>> compression algorithm and also features an extremely fast decoder.
>>>
>>> Kernel Decompression APIs are based on implementation by Yann Collet
>>> ([[http://code.google.com/p/lz4/source/checkout]]).
>>> De/compression Tools are also provided from the site above.
>>>
>>> The initial test result on ARM(v7) based board shows that the size of kernel
>>> with LZ4 compressed is 8% bigger than LZO compressed but the decompressing
>>> speed is faster(especially under the enabled unaligned memory access).
>>>
>>> Test: 3.4 based kernel built with many modules
>>> Uncompressed kernel size: 13MB
>>> lzo: 6.3MB, 301ms
>>> lz4: 6.8MB, 251ms(167ms, with enabled unaligned memory access)
>>>
>>> It seems that it___s worth trying LZ4 compressed kernel image or ramdisk
>>> for making the kernel boot more faster.
>>>
>>> ...
>>>
>>> 20 files changed, 663 insertions(+), 3 deletions(-)
>>>
>>> ...
>>>
>> What's this "with enabled unaligned memory access" thing? You mean "if
>> the arch supports CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS"? If so,
>> that's only x86, which isn't really in the target market for this
>> patch, yes?
>> It's a lot of code for a 50ms boot-time improvement. Does anyone have
>> any opinions on whether or not the benefits are worth the cost?
> BTW, what happened to the proposed LZO update - woudn't it better to merge this first?
>
> Also, under the hood LZ4 seems to be quite similar to LZO, so probably
> LZO speed would also greatly benefit from unaligned access and some other
> ARM optimisations
>
I didn't test with the proposed LZO update you mentioned. Sorry, which
one do you mean?
I did some tests with the latest LZO in the mainline.
As a result, LZO is not faster in an unaligned access enabled on ARM.
Actually Slower.
Decompression time: 336ms(383ms, with unaligned access enabled)
You may refer to https://lkml.org/lkml/2012/10/7/85 to know more about it.
Thanks,
Kyungsik
Thanks,
Kyungsik
next prev parent reply other threads:[~2013-02-01 7:00 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-26 5:50 [RFC PATCH 0/4] Add support for LZ4-compressed kernels Kyungsik Lee
2013-01-26 5:50 ` [RFC PATCH 1/4] decompressors: add lz4 decompressor module Kyungsik Lee
2013-01-26 5:50 ` [RFC PATCH 2/4] lib: add support for LZ4-compressed kernels Kyungsik Lee
2013-01-26 5:50 ` [RFC PATCH 3/4] arm: " Kyungsik Lee
2013-01-26 5:50 ` [RFC PATCH 4/4] x86: " Kyungsik Lee
2013-01-28 22:25 ` [RFC PATCH 0/4] Add " Andrew Morton
2013-01-29 1:16 ` kyungsik.lee
2013-01-29 4:29 ` Nicolas Pitre
2013-01-29 6:18 ` H. Peter Anvin
2013-01-30 10:23 ` Johannes Stezenbach
2013-02-04 2:02 ` Markus F.X.J. Oberhumer
2013-02-04 10:50 ` Russell King - ARM Linux
2013-02-05 11:39 ` Johannes Stezenbach
2013-01-29 7:26 ` Richard Cochran
2013-01-29 10:15 ` Russell King - ARM Linux
2013-01-29 11:43 ` Egon Alter
2013-01-29 12:15 ` Russell King - ARM Linux
2013-02-01 8:15 ` kyungsik.lee
2013-01-30 3:36 ` H. Peter Anvin
2013-01-30 18:33 ` Nicolas Pitre
2013-01-31 21:48 ` H. Peter Anvin
2013-01-31 22:16 ` Nicolas Pitre
2013-01-31 22:18 ` H. Peter Anvin
2013-02-01 2:28 ` Nicolas Pitre
2013-02-01 6:37 ` H. Peter Anvin
2013-01-29 21:09 ` Rajesh Pawar
2013-02-01 7:00 ` kyungsik.lee [this message]
2013-02-04 1:37 ` Markus F.X.J. Oberhumer
2013-01-29 22:55 ` David Sterba
2013-01-30 4:03 ` 이경식
2013-01-30 4:27 ` 이경식
2013-02-01 7:13 ` kyungsik.lee
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