Messages in this thread | | | Subject | Re: 2.6.15-rt3 + Open Posix Test Suite | From | Steven Rostedt <> | Date | Tue, 10 Jan 2006 22:53:12 -0500 |
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On Tue, 2006-01-10 at 15:03 -0800, Daniel Walker wrote: > It's worth noting that a few tests in the current Open Posix Test Suite > hang RT systems. > > Specifically this test (hope this url comes through), > > http://cvs.sourceforge.net/viewcvs.py/*checkout*/posixtest/posixtestsuite/conformance/interfaces/sched_setparam/10-1.c?rev=1.2 > > sched_setparam test 10-1.c and I think 9-1.c . > > The 10-1 test spawns some children at SCHED_FIFO priority 99 , then runs > the following, > > void child_process(){ > alarm(2); > > while(1) { > (*shmptr)++; > sched_yield(); > } > } > > I'm sure this is what's hanging the system, the yield() is one issue. > Another is why the alarm() is never delivered .
This runs a while loop at SCHED_FIFO prio 99? And alarm never happens. Doesn't the alarm get activated by the softirqd that is running at a lower priority? Seems that this is starving out the softirq from getting the alarm.
I believe that Thomas once had priorities attached to the timers. I'd like to see that again, and may even start adding them myself, such that when a process activates a timer, when that timer goes off, the softirq will get the priority of the timer. But this has some complications to be sorted out.
-- Steve
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