CPU service classes for multimedia applications

We present the design, implementation, and experimental results of our soft real time (SRT) system for multimedia applications on top of a general purpose UNIX environment. The SRT system supports multiple CPU service classes for the real time processes based on their processor usage pattern including periodic constant processing time class (PCPT) and periodic variable processing time (PVPT) class. It also provides the following features: reservation and processing time guarantees for the service classes; overrun protection and scheduling algorithm; and system-initiated adaptation strategies. The other unique feature of the SRT system is its easy portability to any operating systems with real time extensions because it is implemented purely in the user space without any modifications to the kernel. We have implemented the SRT system on the Solaris 2.6 operating system with scheduling overhead under 400us and with good performance guarantees