linux-kernel - Re: [RFC] LZO de/compression support

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Date:	Mon, 28 May 2007 04:18:07 -0400
From:	Daniel Hazelton <dhazelton@...er.net>
To:	"Satyam Sharma" <satyam.sharma@...il.com>
Cc:	"Richard Purdie" <richard@...nedhand.com>,
	"Nitin Gupta" <nitingupta910@...il.com>,
	linux-kernel@...r.kernel.org, linux-mm-cc@...top.org,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Andrey Panin" <pazke@...pac.ru>, "Bret Towe" <magnade@...il.com>,
	"Michael-Luke Jones" <mlj28@....ac.uk>
Subject: Re: [RFC] LZO de/compression support - take 4

Test code for this version (take 4) of the minimized LZO1X (from the liblzo 
v2) is complete. 

I don't see a significant slow-down comparing the complete liblzo2 to this 
minimized code on my system (Pentium M 1.73GHz, 1GB Ram, Kubuntu Feisty 
(stock Kubuntu kernel)). Rather, I see the opposite. This *might* have been 
caused by the dynamic linking (or similar) so rather than rely on simply 
doing "time xxx" I actually put checks around the calls to the 
compress/decompress functions themselves.

('Tiny LZO' is what I call Nitins extremely small implementation of 
lzo1x_[de]compress)

Output of the provided "test" script:
10 run averages:
'Tiny LZO':
        Combined: 113.2 usec
        Compression: 77.4 usec
        Decompression: 35.8 usec
'liblzo2':
        Combined: 140.7 usec
        Compression: 94 usec
        Decompression: 46.7 usec

(The "Combined" average is the average time taken for a compress+decompress)

TODO: 
-Implement userspace version of likely/unlikely
-Implement cpu_to_le16 so code functions on BE systems

DRH

Download attachment "lzo1x-test.tar.bz2" of type "application/x-tbz" (6279 bytes)