On 26.11.2007 16:30:31 Vincent Hennebert wrote: > Hi, > > A bit late, but still... > > Jeremias Maerki wrote: > > As you probably noticed, I'm looking again into improving the > > performance of the intermediate format: > > http://wiki.apache.org/xmlgraphics-fop/AreaTreeIntermediateXml > > <snip what="IFPainter vs area Tree"/> > > If I understand well, the intermediate format would be some kind of > abstract low-level page description format that would serve as a basis > for transformation into other (even more) low-level formats. That could > have been PDF as well, but XML is simpler and more straightforward to > manipulate thanks to well-defined APIs like SAX. I guess this is roughly > a matter of moving to a common earlier point the complexity that is > currently duplicated in each renderer. Did I get the picture right?
Yes > I second Adrian in saying that I like this approach which looks quite > elegant to me. Even if that would probably be good to cleanup the area > tree code a bit, which would have occured with the 2nd approach, I like > this one and would probably vote for it. > > > > In contrast to the above, there's an additional way to increase > > performance without much work: > > We just make use of modern multi-core CPUs. FOP is mostly > > single-threaded. If you look at the CPU usage in a dual-core machine, > > you'll see that it will stay at about 50% when rendering. If we do area > > tree parsing in the main thread and rendering in another we can do both > > at the same time. That's an easy way to decouple the two tasks. > > I don’t have the same concerns as Chris but I also don’t think it’s > a good idea. I believe the code base simply isn’t clean enough to switch > to multi-threading. I think we will run into synchronisation issue that > will be a real nightmare to solve. > Although I do think several threads would make sense from a software > architecture point of vue, but we are no near ready to it IMHO. That > might indeed change once we upgrade the minimal compliance to Java 1.5 > and its java.util.concurrent library. Ok, that idea is postponed in that case, although it might itch me one rainy sunday. ;-) Jeremias Maerki