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

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Date:	Tue, 29 May 2007 19:32:03 -0400
From:	Daniel Hazelton <dhazelton@...er.net>
To:	"Nitin Gupta" <nitingupta910@...il.com>
Cc:	"Bret Towe" <magnade@...il.com>,
	lkml <linux-kernel@...r.kernel.org>, linux-mm-cc@...top.org,
	linuxcompressed-devel@...ts.sourceforge.net,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Richard Purdie" <richard@...nedhand.com>,
	"Satyam Sharma" <satyam.sharma@...il.com>
Subject: Re: [RFC] LZO de/compression support - take 6

I just noticed a bug in my testbed/benchmarking code. It's fixed, but I 
decided to compare version 6 of the code against the *unsafe* decompressor 
again. The results of the three runs I've put it through after changing it to 
compare against the unsafe decompressor were startling. `Tiny's` compressor 
is still faster - I've seen it be rated up to 3% faster. The decompressor, 
OTOH, when compared to the unsafe version (which is the comparison that 
started me on this binge of hacking), is more than 7% worse. About 11% slower 
on the original test against a C source file, and about 6% slower for random 
data. However, looking at the numbers involved, I can't see a reason to keep 
the unsafe version around - the percentages look worse than they are - from 1 
to 3 microseconds. (well, the compressed-cache people might want those extra 
usecs - but the difference will never be noticeable anywhere outside the 
kernel)

DRH

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