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From: Jeff Garzik <jgarzik@pobox.com>
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
Date: Thu, 16 Aug 2012 12:48:49 -0400	[thread overview]
Message-ID: <502D2471.407@pobox.com> (raw)
In-Reply-To: <20120816162051.GK11413@one.firstfloor.org>

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





WARNING: multiple messages have this Message-ID (diff)
From: jgarzik@pobox.com (Jeff Garzik)
To: linux-arm-kernel@lists.infradead.org
Subject: [GIT PULL] Update LZO compression
Date: Thu, 16 Aug 2012 12:48:49 -0400	[thread overview]
Message-ID: <502D2471.407@pobox.com> (raw)
In-Reply-To: <20120816162051.GK11413@one.firstfloor.org>

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

  reply	other threads:[~2012-08-16 16:48 UTC|newest]

Thread overview: 35+ 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
2012-08-14 12:39   ` Johannes Stezenbach
2012-08-15 12:02   ` Markus F.X.J. Oberhumer
2012-08-15 12:02     ` Markus F.X.J. Oberhumer
2012-08-15 14:45     ` Johannes Stezenbach
2012-08-15 14:45       ` Johannes Stezenbach
2012-08-16  6:27       ` Markus F.X.J. Oberhumer
2012-08-16  6:27         ` Markus F.X.J. Oberhumer
2012-08-16 15:06         ` Johannes Stezenbach
2012-08-16 15:06           ` Johannes Stezenbach
2012-08-16 17:25           ` Roman Mamedov
2012-08-16 17:25             ` Roman Mamedov
2012-08-16 17:52             ` Andi Kleen
2012-08-16 17:52               ` Andi Kleen
2012-08-16 18:18               ` Geert Uytterhoeven
2012-08-16 18:18                 ` Geert Uytterhoeven
2012-08-16 18:55                 ` james northrup
2012-08-16 22:17                   ` Andi Kleen
2012-08-16 22:17                     ` Andi Kleen
2012-08-17  1:23                     ` Mitch Harder
2012-08-17  1:23                       ` Mitch Harder
2012-09-07 21:31                   ` Andi Kleen
2012-09-07 21:31                     ` Andi Kleen
2012-08-16 18:57                 ` james northrup
2012-08-16 15:21         ` Jeff Garzik
2012-08-16 15:21           ` Jeff Garzik
2012-08-16 16:20           ` Andi Kleen
2012-08-16 16:20             ` Andi Kleen
2012-08-16 16:48             ` Jeff Garzik [this message]
2012-08-16 16:48               ` Jeff Garzik
2012-08-16 17:22               ` Johannes Stezenbach
2012-08-16 17:22                 ` Johannes Stezenbach

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