The SRMS Workbench

The SRMS Workbench is a software system developed to demonstrate the notion of Statistical QoS employed in SRMS [AtlasBestavros:1998]. The SRMS Workbench includes: (1) the SRMS schedulability analyzer (QoS negotiator), and (2) a SRMS simulator (Basic SRMS + all extensions). These two components are packaged into a Java Applet that can be executed remotely on any Java-capable Internet browser. For comparison, other scheduling algorithms, including RMS [LiuLayland:1973] and SSJAC [AtlasBestavros:1998] are included. Through a simple GUI, the SRMS Workbench allows users to specify a set of periodic tasks, each with (a) its own period, (b) the distributional characteristics of its periodic resource requirements (e.g. Poisson, Pareto, Normal, Exponential, Gamma, etc.), (c) its desired QoS as a lower bound on the percentage of deadlines to be met, and (d) a criticality/importance index indicating the value of the task (relative to other tasks in the task set). Once the task set is specified, the SRMS Workbench allows the user to check for schedulability under SRMS. If the task set is schedulable, the SRMS Workbench generates the appropriate allowance for each task and allows the user to create an animated simulation of the task system, which can be executed and profiled. If the task set is not schedulable, the SRMS Workbench informs the user of that fact and suggests (as part of the QoS negotiation) an alternative set of feasible QoS requirements that reflects the specified criticality/importance index of the tasks in the task set. The SRMS Workbench is available on the Web at http://www.cs.bu.edu/groups/realtime/SRMSworkbenc