linux-kernel - Re: [GIT PULL] Update LZO compression

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Message-ID: <20120816150647.GA22010@sig21.net>
Date:	Thu, 16 Aug 2012 17:06:47 +0200
From:	Johannes Stezenbach <js@...21.net>
To:	"Markus F.X.J. Oberhumer" <markus@...rhumer.com>
Cc:	linux-kernel@...r.kernel.org, Andi Kleen <andi@...stfloor.org>,
	chris.mason@...ionio.com, linux-btrfs@...r.kernel.org,
	Nitin Gupta <ngupta@...are.org>,
	Richard Purdie <rpurdie@...nedhand.com>,
	richard -rw- weinberger <richard.weinberger@...il.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [GIT PULL] Update LZO compression

On Thu, Aug 16, 2012 at 08:27:15AM +0200, Markus F.X.J. Oberhumer wrote:
> On 2012-08-15 16:45, Johannes Stezenbach wrote:
> > 
> > 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)
> 
> My suggested COPY4 replacement probably has a lot of load stalls - maybe some
> ARM expert could have a look and suggest a more efficient implementation.
> 
> In any case, I still would like to see the new code in linux-next because
> of the huge improvements on other modern CPUs.

Well, ~2x speedup on x86 is certainly a good achievement, but there
are more ARM based devices than there are PCs, and I guess many
embedded devices use lzo compressed kernels and file systems
while I'm not convinced many PCs rely on lzo in the kernel.

I know everyone's either busy or on vacation, but it would
be so cool if someone could test on a more modern ARM core,
with the userspace test code I posted it should be easy to do.


Johannes
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