Hi all,
I would like to gather a few ideas concerning a granular, perhaps even
generic approach to better using multicore architectures in Sling.
First, some context:
Basically, I am facing a scenario where we are running a rather
sophisticated web application (lot's of dynamic stuff, closed user
groups, content inheritance, personalized navigation and the like). The
complexity is well under control using a decent bundle-based
modularization in conjunction with Spring, Adaptable etc. Currently, we
have page rendering times* of about 300 - 500ms (with 0 caching
whatsoever) on a multicore architecture with few but high powered cores
(Intel xeon 3.5 Ghz+). However, some of our target platforms are SPARCs
featuring many, but not very powerful cores (e.g. 1.2 Ghz per Thread,
32+ Threads). On such an architecture, the rendering time reaches around
1.5 - 3 Seconds, while, given the known average loads, most of the
available CPUs are completely idle. We are working on reducing the
rendering times further, but profiling clearly shows that there is not
enough room for optimization left to bring this down to our goal of 500ms.
* This means the time to render the complete HTML on the server side.
Now, I'd of course like to make better use of the multicore architecture
for rendering. However, it appears that parallel rendering of JSPs is a
violation of specs (see for example this discussion:
http://osdir.com/ml/java.jasig.uportal.devel/2006-09/msg00094.html).
What I am wondering is if there is something in Sling that could be used
to achieve parallel rendering, even if just for some dedicated
components. I am thinking in the area of includes or maybe by extending
the sling scripting support for JSPs.
Some constraints for the sake of a greater challenge:
- Changing the target architecture is not an option in the near future
- Likewise is shifting some stuff to the client (i.e. more AJAX)
- Caching is *not* the solution (we can only do this for part of the
content, but the load times have to be acceptable when the cache is
cleared...).
- There is a 2 GB memory limit, thus thread contention means quick death :-)
Any ideas, hints or opinions are highly appreciated.
Regards,
Olaf
