Great, I would suggest just one test more. Try to convert a PDF with an huge raster image > 400Mb. The xput gain of lcms2 should be evident in this case. Regards. Marti
-----Original Message----- From: Albert Astals Cid [mailto:[email protected]] On Behalf Of Albert Astals Cid Sent: sábado, 28 de enero de 2012 16:48 To: [email protected] Cc: Maria, Marti; [email protected]; Till Kamppeter; Koji Otani Subject: Re: [poppler] Migrating poppler to liblcms2 from liblcms1 El Divendres, 27 de gener de 2012, a les 18:23:50, Albert Astals Cid va escriure: > El Divendres, 27 de gener de 2012, a les 10:39:18, Maria, Marti va escriure: > > Bon dia Albert, > > Hola > > > That makes a lot of sense. Lcms2 spends more time on optimizing the > > transform in order to make it faster. That means create transform is > > currently slower that lcms1 but applying transforms is way faster. > > This was indeed a design decision, as most of time creation of > > transforms happens only once at the very beginning and then this > > transform is applied to huge amounts of raster. The performance > > tests I send didn't take creation time into account. > > > > I will take this action item to review creation time in the next > > release. > > Otherwise, you may consider reusing transforms. > > We reuse the transforms, it is just that this file has lots of them. > > > That would speed up both > > lcms1 and lcms2. If this is not feasible, there is a flags > > cmsFLAGS_NOOPTIMIZE, that makes transform creation fast, at the > > expense of slower dotransfom operation. This is not recommended at > > all because you disable all optimizations, but may solve the issue > > when creating transforms that are applied only to few bytes. > > Not sure if i can now to how many bytes it'll be applied but i'll do > some testing and maybe just enable it for the time being so at least > we have the same behaviour than when using lcms1, might not be faster > but we not slower either. Using cmsFLAGS_NOOPTIMIZE brings back altona_technical_1v2_x3.pdf to an acceptable speed again. Koji can you please update your patch so it uses the cmsFLAGS_NOOPTIMIZE when compiling with lmcs2? Albert > > Thanks, > Albert > > > Again, thanks for reporting. I'm putting the transform creation time > > issue high in my priority list. > > > > Best regards > > > > Marti Maria, Color Engineer > > HP Large Format Printers Division - Barcelona [email protected] > > > > > > > > -----Original Message----- > > From: Albert Astals Cid [mailto:[email protected]] On Behalf Of > > Albert Astals Cid Sent: jueves, 26 de enero de 2012 19:43 > > To: [email protected] > > Cc: Maria, Marti; Till Kamppeter; [email protected] > > Subject: Re: [poppler] Migrating poppler to liblcms2 from liblcms1 > > > > El Dilluns, 23 de gener de 2012, a les 11:16:03, Maria, Marti va escriure: > > > Hi, > > > In my testings lcms2 is significantly faster that lcms1 except > > > when using floating point, then lcms2 favors precision. > > > > Is this precision is so important to justify a 10x slowliness? Maybe > > it'd be a good idea to have a fallback fast mode for those not > > willing to take that 10x hit? > > > > > http://littlecms2.blogspot.com/2010/03/xput-comparative-119-vs-20. > > > ht > > > ml > > > > > > Altona test does many different color conversions it would be > > > interesting to know which transformation is going slow. > > > > Attached the callgrind output of running poppler there, you can see > > the time is almost totally spent on creating the transforms. > > > > Wild guess: I'm wondering if the thing is that not transformations > > are all precalculated (meaning a faster overall if you do lots of > > access) and previously they were done each time and thus if we end > > up doing "few" transformations it was just much faster? > > > > Cheers, > > > > Albert > > > > > Regards > > > Marti > > > > > > ________________________________________ > > > From: Till Kamppeter [[email protected]] > > > Sent: Monday, January 23, 2012 8:58 AM > > > To: Albert Astals Cid > > > Cc: [email protected]; 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 > > > > > > _______________________________________________ > > > poppler mailing list > > > [email protected] > > > http://lists.freedesktop.org/mailman/listinfo/poppler > > _______________________________________________ > poppler mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/poppler _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
