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
