Re: [GIT PULL] Update LZO compression

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: Thu, 16 Aug 2012 17:06:47 +0200	[thread overview]
Message-ID: <20120816150647.GA22010@sig21.net> (raw)
In-Reply-To: <502C92C3.7090701@oberhumer.com>

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