A model and stack implementation of multiple environments

Abstract

Many control and access environment structures require that storage for a procedure activation exist at times when control is not nested within the procedure activated. This is straightforward to implement by dynamic storage allocation with linked blocks for each activation, but rather expensive in both time and space. This paper presents an implementation technique using a single stack to hold procedure activation storage which allows retention of that storage for durations not necessarily tied to control flow. The technique has the property that, in the simple case, it runs identically to the usual automatic stack allocation and deallocation procedure. Applications of this technique to multitasking, coroutines, backtracking, label-valued variables, and functional arguments are discussed. In the initial model, a single real processor is assumed, and the implementation assumes multiple-processes coordinate by passing control explicitly to one another. A multiprocessor implementation requires only a few changes to the basic technique, as described.This paper presents a new approach to the analysis of performance of the various key-to-address transformation methods. In this approach the keys in a file are assumed to have been selected from the key space according to a certain probabilistic selection algorithm. All files with the same number of keys selected from this key space will be suitably weighted in accordance with the algorithm, and the average performance of the transformation methods on these files will be used as the potential of these methods. Using this analysis, methods with the same overall performance can be classified and key distributions partial to certain transformations can be identified. All this can be done analytically. The approach is applied to a group of transformation methods using files whose keys are selected randomly.

MTSS

“…One such attempt consists of allocating stacks on the heap [Grunwald and Neves 1996;Behren et al 2003]. In older schemes, which used heap-based allocation of stacks [Bobrow and Wegbreit 1973;Hauck and Dent 1968], the activation records are allocated on the heap, and explicitly deallocated when the procedure returns. Thus, no task runs out of memory, unless there is no space left globally.…”

A comparative analysis of fine-grain threads packages

“…A stacklet is a contiguous region of memory on a single processor that acts like a normal stack but contains enough extra information to handle independent threads of control if necessary. Multiple stacklets can be allocated on a single stack to form a tree structure commonly known as a cactus stack [BW73].…”

Experience with an uncommon Lisp

“…One of the more important events relating to the design of the new IBM Research Lisp system was the publication of the Bobrow and Wegbreit paper [Bobrow and Wegbreit 1973] proposing a new control structure, the spaghetti stack. We immediately seized on the elegance and flexibility of this idea.…”