Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm2-V0.7.1

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• Maybe in reply to: Ingo Molnar: "[patch] Real-Time Preemption, -RT-2.6.10-rc1-mm2-V0.7.1"
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To: Ingo Molnar <mingo@elte.hu>
Date:	Thu, 4 Nov 2004 10:53:58 -0600

>> I can set those as well but then I'd probably have to follow with
>> the X server and everything else in the chain. The starvation problem
>> ripples across the system.
>
>X should be scheduled on the other CPU just fine. Only per-CPU kernel
>threads (which are affine to their particular CPU) are affected by this
>problem - ordinary tasks not. I.e. the system threads that have /0 and
>/1 in their name. In theory you should not even need to chrt the hardirq
>threads, those should schedule fine too.
Perhaps "should be fine" but the test I just ran indicates otherwise.
The kernel is -V0.7.7 plus the patch you just sent me.
All IRQ and /# tasks were set to RT priority 99.

Started the X test and the display locked up almost immediately while
ping responses continued to flow on a regular basis. After several seconds
I could see the display update / move the mouse & then the display locked
up again. It went back and forth a couple cycles and did not get unstuck
until the RT audio application quit (over 250000 samples).

I will let it run to see if I can reproduce the deadlock or if the symptoms
change with one of the other tests.

--Mark H Johnson
  <mailto:Mark_H_Johnson@raytheon.com>

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• Previous message: Adam Heath: "Re: support of older compilers"
• Maybe in reply to: Ingo Molnar: "[patch] Real-Time Preemption, -RT-2.6.10-rc1-mm2-V0.7.1"
• Next in thread: Mark_H_Johnson_at_raytheon.com: "Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm2-V0.7.1"
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