A Dimecres 26 Setembre 2007, Krzysztof Kowalczyk va escriure: > So I started looking at perf again. > > The first improvement is ~4% rendering speedup for PDF in > https://bugs.freedesktop.org/show_bug.cgi?id=11849. > > From the profile it looked like in this case a great deal (129899) of > SplashPath objects was created/destroyed, yet at any given time only a > few were allocated at the same time, so a small cache to recycle > objects improves that. With this PDF I get the following changes for > alloc functions counts: > > before: > gfree 0.31 0.31 100.00 1092627 > gmalloc 0.18 0.18 100.00 548663 > grealloc 0.13 0.13 100.00 389808 > > after: > gfree 0.16 0.16 100.00 702930 > gmalloc 0.14 0.14 100.00 548663 > grealloc0.03 0.03 100.00 98382 > > I measure speed up with the newly added test/perf-test, using release > build on windows, like this: > perftest.exe -timings c:\kjk\downloads\slow00.pdf > > For comparison I take the smallest number out of few runs. > > You'll see the code when I solve my branch pushing troubles. > > There are some issues: > * this applies to all caches: cache must be emptied at some point, > especially at the end, in order to not be seen as a leak. But poppler > doesn't have mandatory init/free function to stuff it. So for now the > user of the library needs to know. I was thinking it could be added > either in PDFDoc destructor (based on assumption that we only want the > cache to live as long as the document, because it really only improves > a small class of PDFs) or in GlobalParams, since it must be > constructed/destructed > * right now a static function SplashFont::create()/destroy() must be > called instead of new/delete SplashFont but I think it could be done > transparently by substituting new/delete for this class. Need to dust > up those C++ books.
I'm very hesitant on the amount of complex code that can introduce just to win a 4% on some specific pdf, but we'll see once your branch is online for testing. And also please, don't overload the new operator, imho that's braindead and using SplashFont::create()/destroy() is just OK. new gives you the "normal" behvaiour and create()/destroy() the cached one, that makes sense. Albert > Also this approach could be used for a few other classes: > SplashXPath 47889 4 48 0 0 574668 > GfxPath 42970 2 80 0 0 > 1718800 > SplashXPathScanner 42074 4 208 0 0 2187848 > SplashSolidColor 38410 20 160 0 0 307280 > > First number is total number of created objects during rendering this > PDF, second is max number of objects existing at the same time. Second > number is important for deciding cache size. If it's 4, cache of size > 4 should provide almost 100% hit ratio (i.e. almost all allocations > should be satisfied from the cache). > > -- kjk > _______________________________________________ > poppler mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/poppler _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
