On Wed, 10 Dec 2014 09:15:00 -0500 Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@xxxxxxxxxx> wrote: > On 12/10/2014 03:25 AM, chase.qi@xxxxxxxxxx wrote: > > From: Chase Qi <chase.qi@xxxxxxxxxx> > > > > Hello, > > > > pip_stress works out of the box on my x86 based laptop, but > > doesn't work on ARM devices, returned 'no inversion incurred'. > > Follow the comment to increase usleep value, 2500 worked for > > pandaboard and 3000 worked for Beaglebone Black board. > > > > I propose that increase the usleep value to 3500 from upstream, > > so that we can use pip_stress right out of the box. > > > > Please let me know if this is acceptable. > > I think they should have modified main() to accept the lock time as a parameter > instead of simply adding some instructions in the comments > > * to show that it works. If you are having difficulty triggering an inversion, > * merely increase the time that the low priority process sleeps while > * holding the lock. (usleep); > * Also note that you have to run as a user with permission to change > * scheduling priorities. > */ > > what I would do is actually > 1. modify main to accept lock_time > 2. send the patch to the rt-tests team > > > I wish we didn't have to deal with timers here. I used barriers when I wrote pi_stress.c and obviously we don't have that luxury with pip_stress.c. I guess the best thing we can do right now is add a parameter to change the default timer value for pip_stress and see if someone comes up with a brilliant state-machine solution that will work between processes :). John and I are about to start a sweep through the tests and will probably come out with a new rt-tests around the first of the year. Clark
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