Views of Storage Allocation in Icon

Ralph E. Griswold

Department of Computer Science
The University of Arizona
Tucson, Arizona

IPD197a
March 24, 1996
http://www.cs.arizona.edu/icon/docs/ipd197.htm

Introduction

The first visualization tool written for Icon was MemMon [1], which provides a relatively literal view of how storage is allocated in Icon. MemMon shows memory regions to scale and objects are shown according to their size and in the order in which they are allocated. Different colors are used to distinguish different types of data.

The visualization tool described here, allocview, takes a different approach. It provides a variety of ways for viewing storage allocation that are more metaphorical than literal.

Like MemMon, allocview uses different colors to represent different types. In some views, an allocated object is shown by an area of color that is proportional to its size. In other views, all allocated objects are the same size. Most views do not attempt to show the relative location in memory where allocation occurs. In some views, location is random. In the jargon of the trade, location does not encode information in these views.

The metaphors of the different views are indicated by their names:

blinker   a blinking light
curtain   a beaded curtain
flowers   flowers with petals
haystack  randomly placed straws
mosaic    a mosaic of tiles
nova      an exploding star
phoenix   buildings rising from the ashes
pinwheel  revolving blades
pulsar	  a pulsating star
rays      random rays
splatter  random dots on a canvas
tapestry  woven threads
vortex    concentric rings
web       a random cobweb
weed      a randomly growing weed

See the examples at the end of this report.

Running the Visualization Tool

When allocview is run, one of the views listed above can be selected. Multiple views can be obtained using Eve[ 2].

allocview is run as follows:

allocview [options] program [arguments]

where program is the program whose allocation is to be monitored. Standard input and output for program can be specified in the usual fashion.

The options available for allocview are:

-v    view, default "pinwheel"
-H    height of view in pixels, default 300
-W    width of view in pixels, default 300
-x    number of columns (where applicable), default 30
-y    number of rows (where applicable), default 30
-s    number of sectors (where applicable), default 240

Colors

In addition to the eight data types for which storage is allocated during program execution, there are several internal types that also are allocated. For example, a list consists of a list block and one or more list-element blocks. In allocview, the same color is used for such related types. (Co-expression allocation is not shown in allocview.)

Examples

mosaic

nova

pinwheel

splatter

tapestry

web

References

1. The Visualization of Dynamic Memory Management in the Icon Programming Language, Ralph E. Griswold and Gregg M. Townsend, Technical Report TR 89-30, Department of Computer Science, The University of Arizona, 1989.

2. Eve: An Icon Monitor Coordinator, Clinton L. Jeffery, Icon Project Document IPD179, Department of Computer Science, The University of Arizona, 1992.

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