[poppler] Migrating poppler to liblcms2 from liblcms1

[Maria, Marti]

Hi,
In my testings lcms2 is significantly faster that lcms1 except when using floating point, then lcms2 favors precision. 

http://littlecms2.blogspot.com/2010/03/xput-comparative-119-vs-20.html

Altona test does many different color conversions it would be interesting to know which transformation is going slow. 

Regards
Marti 

________________________________________
From: Till Kamppeter [till.kamppeter at gmail.com]
Sent: Monday, January 23, 2012 8:58 AM
To: Albert Astals Cid
Cc: poppler at lists.freedesktop.org; Maria, Marti; Sebastien Bacher; Koji Otani
Subject: Re: [poppler] Migrating poppler to liblcms2 from liblcms1

On 01/22/2012 11:18 PM, Albert Astals Cid wrote:
> Same thing, altona_technical_1v2_x3.pdf still goes up from x seconds to 10x
> seconds when going from lcms1 to lcms2.
>
> That is in my opinion not acceptable (of course i'm not ruling out that we in
> poppler are using lcms2 wrong). Till, does your ubuntu work cover fixing the
> regressions of moving from lcms1 to lcms2 or all your work covers is making
> stuff compile?

I downloaded altona_technical_1v2_x3.pdf from
http://www.eci.org/doku.php?id=es:downloads and tried pdftops on Ubuntu
Oneiric (11.10, lcms1) and on Precise (12.04, lcms2, Koji Otani's patch)
and with lcms1 it takes 3.5 seconds and with lcms2 17.5 seconds.

The same problem occurs with Ghostscript: There the same transition
happened from Oneiric to Precise and here Oneiric is much faster with
this file, too. In Precise PDF rendering for printing is done by
Ghostscript and not by Poppler, so lcms2 is already used for printing in
Precise for some time. As there are no performance complaints by users
yet, it seems that for everyday files there is not such a significant
performance loss. and this

Marti, can you check what is the problem with lcms2 and this PDF file
and also why most files are somewhat slower with lcms2?

    Till