Comtrol eCos - Manual (Page 96)

Kernel Real-time Characterization
Suspend [runnable] thread
This test measures the cyg_thread_suspend() call again. In this case, each thread has already been made
runnable (by previous tests).
Yield [only low priority] thread
This test measures the cyg_thread_yield() call. In this case, there are many other runnable threads, but
they are all lower priority than the main thread, thus no thread switches will take place.
Suspend [runnable->not runnable] thread
This test measures the cyg_thread_suspend() call again. The thread being suspended will become non-
runnable by this action.
Kill [runnable] thread
This test measures the cyg_thread_kill() call again. In this case, the thread being killed is currently
runnable, but lower priority than the main thread.
Resume [high priority] thread
This test measures the cyg_thread_resume() call. The thread being resumed is higher priority than the
main thread, thus a thread switch will take place on each call. In fact there will be two thread switches; one to
the new higher priority thread and a second back to the test thread. The test thread exits immediately.
Thread switch
This test attempts to measure the cost of switching from one thread to another. Two equal priority threads are
started and they will each yield to the other for a number of iterations. A time stamp is gathered in one thread
before the
cyg_thread_yield() call and after the call in the other thread.
Scheduler Primitives
Scheduler lock
This test measures the cyg_scheduler_lock() call.
Scheduler unlock [0 threads]
This test measures the cyg_scheduler_unlock() call. There are no other threads in the system and the
unlock happens immediately after a lock so there will be no pending DSR’s to run.
Scheduler unlock [1 suspended thread]
This test measures the cyg_scheduler_unlock() call. There is one other thread in the system which is
currently suspended.
Scheduler unlock [many suspended threads]
This test measures the cyg_scheduler_unlock() call. There are many other threads in the system which
are currently suspended. The purpose of this test is to determine the cost of having additional threads in the
system when the scheduler is activated by way of
cyg_scheduler_unlock() .
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