I am running 2.4.0-test1 kernel with rtlinux-3.0-pre6e and/or
rtlinux-3.0-pre6e and have the following loop:
pthread_make_periodic_np(pthread_self(), gethrtime(),
period*1000);
while(1) {
pthread_wait_np();
TESTBIT_ON();
TESTBIT_OFF();
}
where period = 100 (100 usec). The TESTBIT_ON/TESTBIT_OFF macros do a
single ISA bus I/O to turn on and off the voltage on a test pin which I
can then look at with a scope. I would expect to see something like
this:
__
__ __
| |_____________________________| |_____________________________|
but instead I see this
__ __ __
__ __
| |___|_|_______________________| |___|_|_______________________|
^ ^
These pulses appear 3.338 usecs after the initial pulses, but are
intermittant (i.e. about 5 times/second)
They can only be generated if pthread_wait_np() returns immediately and
does not wait for the 100 usec.
Has anyone else seen this? We are on an 8240 platform of our own
design.
Robert Kavaler
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