IMPROVING REAL-TIME LATENCY PERFORMANCE ON COTS ARCHITECTURES

Abstract

Telemetry systems designed to support the current needs of mission-critical applications often have stringent real-time requirements. These systems must guarantee a maximum worst-case processing and response time when incoming data is received. These real-time tolerances continue to tighten as data rates increase. At the same time, end user requirements for COTS pricing efficiencies have forced many telemetry systems to now run on desktop operating systems like Windows or Unix. While these desktop operating systems offer advanced user interface capabilities, they cannot meet the realtime requirements of the many mission-critical telemetry applications. Furthermore, attempts to enhance desktop operating systems to support real-time constraints have met with only limited success. This paper presents a telemetry system architecture that offers real-time guarantees while at the same time extensively leveraging inexpensive COTS hardware and software components. This is accomplished by partitioning the telemetry system onto two processors. The first processor is a NetAcquire subsystem running a real-time operating system (RTOS). The second processor runs a desktop operating system running the user interface. The two processors are connected together with a high-speed Ethernet IP internetwork. This architecture affords an improvement of two orders of magnitude over the real-time performance of a standalone desktop operating system.