From: markus@oberhumer•com (Markus F.X.J. Oberhumer)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH 0/4] Add support for LZ4-compressed kernels
Date: Mon, 04 Feb 2013 02:37:08 +0100 [thread overview]
Message-ID: <510F10C4.2080903@oberhumer.com> (raw)
In-Reply-To: <510B6829.7050908@lge.com>
On 2013-02-01 08:00, kyungsik.lee wrote:
> 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:
>>>> [...]
>>>>
>>> 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.
In fact you can easily improve LZO decompression speed on armv7 by almost 50%
by adding just a few lines for enabling unaligend access:
armv7 (Cortex-A9), Linaro gcc-4.6 -O3, Silesia test corpus, 256 kB block-size:
compression speed decompression speed
LZO-2005 : 27 MB/sec 84 MB/sec
LZO-2012 : 44 MB/sec 117 MB/sec
LZO-2013-UA : 47 MB/sec 167 MB/sec
Please see my other mail to LKML for details.
Cheers,
Markus
> 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
>
--
Markus Oberhumer, <markus@oberhumer•com>, http://www.oberhumer.com/
next prev parent reply other threads:[~2013-02-04 1:37 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
2013-02-04 1:37 ` Markus F.X.J. Oberhumer [this message]
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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