Kernel Mucking in Top
William LeFebvre
Argonne National Laboratory
Abstract
For many years, the popular program top has aided system
administrations in examination of process resource usage on their
machines. Yet few are familiar with the techniques involved in
obtaining this information. Most of what is displayed by top is
available only in the dark recesses of kernel memory. Extracting
this information requires familiarity not only with how bytes are
read from the kernel, but also what data needs to be read. The
wide variety of systems and variants of the Unix opeating system
in today's marketplace makes writing such a program very
challenging. This paper explores the tremendous diversity in
kernel information across the many platforms and the solutions
employed by top to achieve and maintain ease of portability in
the presence of such divergent systems.
Download the full text of this paper in
ASCII (39,206 bytes) and
POSTSCRIPT (119,086 bytes) form.
To Become a USENIX Member, please see our
Membership Information.