Frame Scheduler Examples

Frame Scheduler Examples

A number of example programs are distributed with the REACT/Pro Frame Scheduler. This section describes them. Only one is reproduced here; the others are found on disk.

The example programs distributed with the Frame Scheduler are found in the directory /usr/react/src/examples. They are summarized in Table i and are discussed in more detail in the topics that follow.

Summary of Frame Scheduler Example Programs
Directory Features of Example
simple
r4k_intr Two processes scheduled on a single CPU at a frame rate slow enough to permit use of printf() for debugging. The examples differ in the time base used; and the r4k_intr code uses a barrier for synchronization.
mprogs Like simple, but the scheduled processes are independent programs.
multi
ext_intr
user_intr
vsync_intr Three synchronous Frame Schedulers running lightweight processes on three processors. These examples are much alike, differing mainly in the source of the time base interrupt.
complete
stop_resume Like multi in starting three Frame Schedulers. Information about the activity processes is stored in arrays for convenient maintenance. The stop_resume code demonstrates frs_stop() and frs_resume() calls.
driver
dintr driver contains a pseudo-device driver that demonstrates the Frame Scheduler device driver interface. dintr contains a program based on simple that uses the example driver as a time base.
sixtyhz
memlock One process scheduled at a 60 Hz frame rate. The activity process in the memlock example locks its address space into memory before it joins the scheduler.
upreuse Complex example that demonstrates the creation of a pool of reusable processes, and how they can be dispatched as activity processes on a Frame Scheduler.

Summary of Frame Scheduler Example Programs
Directory	Features of Example
simple r4k_intr	Two processes scheduled on a single CPU at a frame rate slow enough to permit use of printf() for debugging. The examples differ in the time base used; and the r4k_intr code uses a barrier for synchronization.
mprogs	Like simple, but the scheduled processes are independent programs.
multi ext_intr user_intr vsync_intr	Three synchronous Frame Schedulers running lightweight processes on three processors. These examples are much alike, differing mainly in the source of the time base interrupt.
complete stop_resume	Like multi in starting three Frame Schedulers. Information about the activity processes is stored in arrays for convenient maintenance. The stop_resume code demonstrates frs_stop() and frs_resume() calls.
driver dintr	driver contains a pseudo-device driver that demonstrates the Frame Scheduler device driver interface. dintr contains a program based on simple that uses the example driver as a time base.
sixtyhz memlock	One process scheduled at a 60 Hz frame rate. The activity process in the memlock example locks its address space into memory before it joins the scheduler.
upreuse	Complex example that demonstrates the creation of a pool of reusable processes, and how they can be dispatched as activity processes on a Frame Scheduler.

Basic Example
Example of Scheduling Separate Programs
Examples of Multiple Synchronized Schedulers
Example of Device Driver
Examples of a 60 Hz Frame Rate
Example of Managing Lightweight Processes