Messages in this thread | | | Date | Tue, 19 Dec 2006 22:24:27 +0100 | From | Ingo Molnar <> | Subject | Re: [BUG+PATCH] RT-Preempt: IRQ threads running at prio 0 SCHED_OTHER |
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* Remy Bohmer <l.pinguin@gmail.com> wrote:
> Hello Ingo, > > I am using your yum-distributed kernel 2.6.19.1-rt15, and > unfortunately I experienced very worse latencies. It turned out that > ALL the IRQ threads were all running at prio 0, SCHED_OTHER. > > Looking at the current code in kernel/irq/manage.c, the goal was to > put them at MAX_RT_PRIO, but the call to sys_sched_setscheduler() > fails with EINVAL. I have attached a patch to set them to > (MAX_RT_PRIO-1). This works.
oops - my intention was to set all IRQs and softirqs to SCHED_FIFO prio 50. I have fixed that now in my tree.
prio 99 is pretty extensive and makes it hard to move tasks 'above' hardirq priority, without setting the priority of /every/ IRQ thread. So i picked SCHED_FIFO:50 - at exact half way.
> Further I believe that each application of the RT-kernel requires a > different configuration of these thread-priorities and I prefer to > reconfigure these prios from userland during boot. As these > threadnames contain whitespaces in its name, they make the > shell-scripts unnecessary complex that I use to reconfigure the thread > priorities.
ok - lets try it. Clark: does this impact the set_kthread_prio utility? I've changed "IRQ 123" to "IRQ-123" to make pidof & friends work better.
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