Messages in this thread | | | Date | Thu, 24 Feb 2005 00:23:30 -0500 | From | "Chad N. Tindel" <> | Subject | Re: Xterm Hangs - Possible scheduler defect? |
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> `xterm' is waiting for the other CPU to schedule a kernel thread (which is > bound to that CPU). Once that kernel thread has done a little bit of work, > `xterm' can terminate. > > But kernel threads don't run with realtime policy, so your userspace app > has permanently starved that kernel thread. > > It's potentially quite a problem, really. For example it could prevent > various tty operations from completing, it will prevent kjournald from ever > writing back anything (on uniprocessor, etc). I've been waiting for > someone to complain ;) > > But the other side of the coin is that a SCHED_FIFO userspace task > presumably has extreme latency requirements, so it doesn't *want* to be > preempted by some routine kernel operation. People would get irritated if > we were to do that. > > So what to do?
It shouldn't need to preempt the kernel operation. Why is the design such that the necessary kernel thread can't run on the other CPU?
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