Message-ID: <502D2471.407@pobox.com>
Date: Thu, 16 Aug 2012 12:48:49 -0400
From: Jeff Garzik <jgarzik@pobox.com>
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To: Andi Kleen <andi@firstfloor.org>
CC: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>,
        Johannes Stezenbach <js@sig21.net>, linux-kernel@vger.kernel.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
References: <50299142.2030504@oberhumer.com> <20120814123937.GA14756@sig21.net> <502B8FE3.7080501@oberhumer.com> <20120815144539.GA8300@sig21.net> <502C92C3.7090701@oberhumer.com> <502D100D.2030609@pobox.com> <20120816162051.GK11413@one.firstfloor.org>
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On 08/16/2012 12:20 PM, Andi Kleen wrote:
>> If you think a little bit, I bet you could come up with a solution that
>> operates at cacheline-aligned granularity, something that would be _even
>> faster_ than simply fixing the code to do aligned accesses.
>
> Cache aligned compression is unlikely to compress anything at all.
> Compression algorithms are usually by definition unaligned.

Sure it's a bitstream, but that does not imply the impossibility of 
reading data in in an word-aligned manner.

Maybe cache-aligned is ambitious, because of resultant code bloat, but 
machine-int-aligned is doable and reasonable.

	Jeff


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