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

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Date:	Mon, 28 May 2007 05:21:16 -0400
From:	Daniel Hazelton <dhazelton@...er.net>
To:	"Nitin Gupta" <nitingupta910@...il.com>
Cc:	"Satyam Sharma" <satyam.sharma@...il.com>,
	"Richard Purdie" <richard@...nedhand.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

On Monday 28 May 2007 05:08:54 Nitin Gupta wrote:
> On 5/28/07, Daniel Hazelton <dhazelton@...er.net> wrote:
> > On Monday 28 May 2007 04:37:04 Nitin Gupta wrote:
> > > On 5/28/07, Daniel Hazelton <dhazelton@...er.net> wrote:
>
> <snip>
>
> > > As you mentioned in your mail, you are using lzo1x_1_11_compress()
> > > which is slower than what I ported (which is same as what is exported
> > > by miniLZO). So, can you please test with the version ported  - this
> > > is found in lzo/src/lzo1x_1.c (or in minilzo.c).
> > > Also, can you please use 'take 5' for your next testing?
> > >
> > > Thanks,
> > > Nitin
> >
> > Will do.  (that's DBITS=15, correct?)
>
> That's D_BITS=14
>
> > However, when I averaged it 100 times, lzo1x_1_11_compress() showed
> > better speed than your implementation - about 1.5% faster.
>
> I don't yet have any explanation for this.
>
> > The *unsafe*
> > decompressor, however, only shows about a 1.2% speed advantage over the
> > safe decompressor.
> >
> > DRH


New testbed based on minilzo complete.
Results from run using 1000 runs to generate averages:
1000 run averages:
'Tiny LZO':
        Combined: 55.196 usec
        Compression: 37.132 usec
        Decompression: 18.064 usec
'miniLZO':
        Combined: 55.785 usec
        Compression: 40.862 usec
        Decompression: 14.923 usec

(using (tiny/full)/100 for percentages:
'Tiny' is 0.9% faster on average
Same for the Compression
'safe' decompressor from tiny is 1.2% slower than unsafe from minilzo)

Newer version attached - same TODO items as the previous.

DRH

Download attachment "lzo1x-test-2.tar.bz2" of type "application/x-tbz" (26704 bytes)