From: Johannes Stezenbach <js@sig21.net>
To: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
chris.mason@fusionio.com, linux-btrfs@vger.kernel.org,
Nitin Gupta <ngupta@vflare.org>,
Richard Purdie <rpurdie@openedhand.com>,
richard -rw- weinberger <richard.weinberger@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [GIT PULL] Update LZO compression
Date: Wed, 15 Aug 2012 16:45:39 +0200 [thread overview]
Message-ID: <20120815144539.GA8300@sig21.net> (raw)
In-Reply-To: <502B8FE3.7080501@oberhumer.com>
[-- Attachment #1: Type: text/plain, Size: 2648 bytes --]
Hi Marcus,
On Wed, Aug 15, 2012 at 02:02:43PM +0200, Markus F.X.J. Oberhumer wrote:
> On 2012-08-14 14:39, Johannes Stezenbach wrote:
> > On Tue, Aug 14, 2012 at 01:44:02AM +0200, Markus F.X.J. Oberhumer wrote:
> >> On 2012-07-16 20:30, Markus F.X.J. Oberhumer wrote:
> >>>
> >>> As stated in the README this version is significantly faster (typically more
> >>> than 2 times faster!) than the current version, has been thoroughly tested on
> >>> x86_64/i386/powerpc platforms and is intended to get included into the
> >>> official Linux 3.6 or 3.7 release.
> >>>
> >>> I encourage all compression users to test and benchmark this new version,
> >>> and I also would ask some official LZO maintainer to convert the updated
> >>> source files into a GIT commit and possibly push it to Linus or linux-next.
> >
> > Sorry for not reporting earlier, but I didn't have time to do real
> > benchmarks, just a quick test on ARM926EJ-S using barebox,
> > and found in the new version decompression is slower:
> > http://lists.infradead.org/pipermail/barebox/2012-July/008268.html
>
> I can only guess, but maybe your ARM cpu does not have an efficient
> implementation of {get,put}_unaligned().
Yes, ARMv5 cannot do unaligned access. ARMv6+ could, but
I think the Linux kernel normally traps it for debug,
all ARM seem to use generic {get,put}_unaligned() implementation
which use byte access and shift.
> Could you please try the following patch and test if you can see
> any significant speed difference?
It isn't. I made the attached quick hack userspace code
using ARM kernel headers and barebox unlzop code.
(new == your new code, old == linux-3.5 git, test == new + your suggested change)
(sorry I had no time to clean it up)
I compressed a Linux Image with lzop (lzop <arch/arm/boot/Image >lzoimage)
and timed uncompression:
# time ./unlzopold <lzoimage >/dev/null
real 0m 0.29s
user 0m 0.19s
sys 0m 0.10s
# time ./unlzopold <lzoimage >/dev/null
real 0m 0.29s
user 0m 0.20s
sys 0m 0.09s
# time ./unlzopnew <lzoimage >/dev/null
real 0m 0.41s
user 0m 0.30s
sys 0m 0.10s
# time ./unlzopnew <lzoimage >/dev/null
real 0m 0.40s
user 0m 0.30s
sys 0m 0.10s
# time ./unlzopnew <lzoimage >/dev/null
real 0m 0.40s
user 0m 0.29s
sys 0m 0.11s
# time ./unlzoptest <lzoimage >/dev/null
real 0m 0.39s
user 0m 0.28s
sys 0m 0.11s
# time ./unlzoptest <lzoimage >/dev/null
real 0m 0.39s
user 0m 0.27s
sys 0m 0.11s
# time ./unlzoptest <lzoimage >/dev/null
real 0m 0.39s
user 0m 0.27s
sys 0m 0.11s
FWIW I also checked the sha1sum to confirm the Image uncompressed OK.
Johannes
[-- Attachment #2: lzo-bench.tar.gz --]
[-- Type: application/octet-stream, Size: 54224 bytes --]
next prev parent reply other threads:[~2012-08-15 14:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-13 23:44 [GIT PULL] Update LZO compression Markus F.X.J. Oberhumer
2012-08-14 3:15 ` Andi Kleen
2012-08-14 10:10 ` Markus F.X.J. Oberhumer
2012-08-14 12:39 ` Johannes Stezenbach
2012-08-15 12:02 ` Markus F.X.J. Oberhumer
2012-08-15 14:45 ` Johannes Stezenbach [this message]
2012-08-16 6:27 ` Markus F.X.J. Oberhumer
2012-08-16 15:06 ` Johannes Stezenbach
2012-08-16 17:25 ` Roman Mamedov
2012-08-16 17:52 ` Andi Kleen
2012-08-16 18:18 ` Geert Uytterhoeven
[not found] ` <CAPkEcwgv6f5B+Mrw7kzrHcZ5JZ+Yr0o=bLdoFqCB-e4CLiVx5A@mail.gmail.com>
2012-08-16 22:17 ` Andi Kleen
2012-08-17 1:23 ` Mitch Harder
2012-09-07 21:31 ` Andi Kleen
2012-08-16 15:21 ` Jeff Garzik
2012-08-16 16:20 ` Andi Kleen
2012-08-16 16:48 ` Jeff Garzik
2012-08-16 17:22 ` Johannes Stezenbach
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120815144539.GA8300@sig21.net \
--to=js@sig21.net \
--cc=andi@firstfloor.org \
--cc=chris.mason@fusionio.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=markus@oberhumer.com \
--cc=ngupta@vflare.org \
--cc=richard.weinberger@gmail.com \
--cc=rpurdie@openedhand.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).