We introduce the Forseti system, which is a principled approach for holistic memory management. It permits a sysadmin to specify the total physical memory resource that may be shared between all concurrent virtual machines on a physical node. Forseti models the heap size versus application throughput for each virtual machine, and seeks to maximize the combined throughput of the set of VMs based on concepts from economic utility theory. We evaluate the Forseti system using a standard Java managed runtime, i.e. OpenJDK. Our results demonstrate that Forseti enables dramatic reductions (up to 5x) in heap footprint without compromising application execution times.

The Insense VM is a specialised Java virtual machine for running Insense programs on wireless sensor nodes. The VM runs on top of InceOS, a purpose-built operating system. A split VM architecture is used, in which Insense programs are compiled to Java classes, then linked and compacted on a more powerful machine into a form suitable for execution by the VM. Measurements demonstrate that the virtual machine achieves good performance and memory usage for realistic Insense programs.

Multiple virtual machine (VM) workloads are increasingly common, given the growth of managed enterprise application systems and consolidated virtual servers. Until now, there has been no principled approach to partitioning memory resource between multiple co-located VMs. In this paper, we develop a general framework for multi-VM heap sizing, based on the principle of utility maximization from microeconomic theory. We apply utility maximization to static heap sizing, and obtain performance improvements slightly better than current best-practice static heap sizing, and comparable with HotSpot ergonomics (current best-practice dynamic heap sizing). The major advantage of our approach is its simplicity and predictable resource utilization.

Feature-creep is a well-known phenomenon in software systems. In this paper, we argue that feature-creep also occurs in the domain of programming languages. Recent languages are more expressive than earlier languages. However recent languages generally extend rather than replace the syntax (sometimes) and semantics (almost always) of earlier languages. We demonstrate this trend of agglomeration in a sequence of languages comprising Pascal, C, Java, and Scala. These are all block-structured Algol-derived languages, with earlier languages providing explicit inspiration for later ones. We present empirical evidence from several language-specific sources, including grammar definitions and canonical manuals. The evidence suggests that there is a trend of increasing complexity in modern languages that have evolved from earlier languages.