The code is really trivial: a 4 element stack, in delete objects are pushed on stack (if there's space), in new objects are popped from stack.
What's brainded about overloading new/delete? After some thinking I think overloading is better because it has one big advantage: it requires no changes to poppler code (other than adding some more code). In that it makes merges with xpdf easier. Without overloading you need to replace every new/delete SplashPath with SplashPath::create/SplashPath::destroy, which results in more changes. -- kjk On 9/26/07, Albert Astals Cid <[EMAIL PROTECTED]> wrote: > 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 > _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
