[specialist]

> C code has much better control over the layout of data in memory.

Yes. This presentation really drives that point in.

Building Memory-Efficient Java Applications: Practices and Challenges http://www.cs.virginia.edu/kim/publicity/pldi09tutorials/mem...

(There are plenty of other sources too.)

Our Java study group tackled this paper. To prepare for the discussion, I tried to put my XML document object model implementation on a diet. Super fun. Modest benefits.

> You can work around the GC issues and modern compilers work around > the interpretation overhead, but a C program is going to tend to > have the easiest time ensuring that its working set fits into cache.

As I understand it (h/t Joe Bowbeer), Doug Lea and others have been doing very cool work micro tuning data structures suitable for use on multicore systems. So it's possible. But definitely not trivial; certainly beyond my abilities.