Memory barriers, or fences, are a set of processor instructions used to apply ordering limitations on memory operations. This article explains the impact memory barriers have on the determinism of multi-threaded programs. We'll look at how memory barriers relate to JVM concurrency constructs such as volatile, synchronized and atomic conditionals.
In this presentation from the JVM Languages Summit 2008, Charles Nutter discusses bringing JRuby to the JVM, why Ruby is hard to implement, JIT compilation, precompilation, core Ruby implementation, Java library method access, method call semantics, scopes, open classes, heap-based frames, library challenges, strings, regexps, I/O, green threads, POSIX features, C lib support and future plans.
In this presentation from the JVM Languages Summit 2008, John Pampuch discusses the HotSpot compiler, the history of Java performance, HotSpot development philosophies and challenges, optimization, inlining, virtual methods, loop unrolling, constant folding, escape analysis, synchronization improvements, JVM library improvements, processor-specific optimizations, and tips for better performance.
Last week, Oracle released Java7 to great acclaim. However, an issue identified by the Apache Lucene project pointed to a specific hotspot optimisation bug which kicks in when a loop is executed more than 10,000 times. How serious is this issue, and does it warrant the kind of negative press that has been played out over the last few days?
Oracle principal engineer and former Sun employee Mark Reinhold talks about Oracle's plans to merge the Hotspot and JRockit JVMs.
A new intermediate representation (IR) for JRuby code enables many optimizations and could bring the next performance boost. InfoQ talked to Subbu Sastry who works on the IR.
