On Tue, 2004-10-12 at 12:18 +0300, Jakub Pavelek wrote: > Hi all, > > we have had a look at our performance with Fontconfig 2.2.96 and have > some questions: > > 1) there seems to be a huge number of strcmp operations when handling > the fonts. In my test run I got over a million of such comparisons > originated form Fontconfig! Element names are compared again and again. > Do we feel this should be optimized? Does anyone work on that already? What kind of operations are using? Even better, could you create a small benchmark that simulates what your program is doing? There are certainly some things that are known slow - the fact that all FcFontMatch operations involve a linear scan could be improved by adding some hash table indices. (There's a bug in bugzilla about that.) But I'm a little surprised of 1 million + strcmps if you are working with a small number of fonts. I don't really know of any work being done. For desktop performance memory usage and startup time is definitely people's main concern with fontconfig at the moment. That's partly because common toolkits (Pango and I think also Qt) have higher levels of caching above fontconfig. > 2) The usage of floating point types. Those matching results are > "double" even though majority of comparisons do not return any real > floating point value. Not a problem on x86 but when run on ARM this > becomes really bad really fast. > Should we think about optimizations here too? Anyone working on that > already? I haven't heard of anybody working on that. It's probably possible to replace the doubles with strcol-style sort keys or similar, though it will certainly not help performance where doubles *are available. Regards, Owen -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: This is a digitally signed message part Url : http://freedesktop.org/pipermail/fontconfig/attachments/20041012/16d44c7a/attachment.pgp
