Applications that manipulate digital audio and video are rapidly being added to workstations. Such computations can often consume the resources of an entire machine. By incorporating a “realtime” process scheduler, UNIX System V Release 4 (SVR4), the most common basis of workstation operating systems, claims to provide system support for multimedia applications. Our quantitative measurements of real application performance demonstrate that this process scheduler is largely ineffective and can even produce system lockup. While SVR4 UNIX provides many controls for changing scheduler performance, they are virtually impossible to use successfully. Furthermore, the existence of a realtime static priority process scheduler in no way allows a user to deal with these problems.This paper provides a quantitative analysis of real system behavior, demonstrates why it is not possible to obtain the kind of behavior desired with the mechanisms currently provided by the system, and presents modifications to improve the situation.
[1]
Steve Evans,et al.
Optimizing UNIX Resource Scheduling for User Interaction
,
1993,
USENIX Summer.
[2]
James Gettys,et al.
The X window system
,
1986,
TOGS.
[3]
Maurice J. Bach.
The Design of the UNIX Operating System
,
1986
.
[4]
J. Duane Northcutt,et al.
Workstation Support for Time-Critical Applications
,
1991,
NOSSDAV.
[5]
Mark Smith,et al.
Beyond Multiprocessing: Multithreading the SunOS Kernel
,
1992,
USENIX Summer.
[6]
J. Duane Northcutt,et al.
Bus Bandwidth Management in a High Resolution Video Workstation
,
1992,
NOSSDAV.
[7]
Ben Shneiderman,et al.
Designing the user interface (2nd ed.): strategies for effective human-computer interaction
,
1992
.