| Abstract: |
Servers have been proposed to implement resource reservations on shared resources. Such reservations isolate the temporal behavior of tasks sharing the shared resources, thereby providing
performance guarantees to tasks independent of other tasks. In existing work, resource reservation has been synonymous to utilization (also called bandwidth) on the resource, i.e., we can reserve
only a constant fraction of the resource utilization via a server. Such reservation schemes are not suited to serve interrupt-like tasks: tasks that occur seldom but require quick service or
tasks with jitter. With this motivation, we present a generalized server algorithm, called Demand Bound Server (DBS), whose offered service is characterized by the demand bound function (dbf) of
the task it serves. We show that schedulability of DBS tightly follows that of EDF, and if schedulable a DBS provides a performance guarantee as requested by the dbf of the task. We present an
implementation of DBS when the dbf is a shifted-periodic curve and characterize its overhead. We also present efficient composition operations on DBS that widen the class of implemented servers
to tightly serve tasks arising in most practical settings. |
