Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.6.8

K.R. Foley
2004-11-02T17:54:12Z

Ingo Molnar wrote:
> * Thomas Gleixner <tglx@linutronix.de> wrote:
>
>
>>>Thomas, can you confirm that this kernel fixes the irqs-off latencies?
>>>(the priority loop indeed was done with irqs turned off.)
>>
>>The latencies are still there. I have the feeling it's worse than 0.6.2.
>
>
> update to others: Thomas debugged this problem today and found the place
> that kept irqs disabled for a long time: it was update_process_times().
> (which i recently touched to break latencies there - but forgot that the
> lock is an irqs-off lock!)
>
> i've uploaded a fixed kernel (-V0.6.8) to:
>
> http://redhat.com/~mingo/realtime-preempt/
>
> (this kernel also has the module-put-unlock-kernel fix that should solve
> the other warning reported by Thomas and Bill.)
>
> Ingo
>

This one initially booted fine on my SMP workstation at the office. Ran
for about 1 hr. 10 mins. then locked with no indications as to why. Then
failed reboot after hitting the reset switch. The last thing that I saw
on the console seems to match the following that I found in the log:

Nov 2 11:21:49 swdev14 rc: Starting readahead: succeeded
Nov 2 11:21:50 swdev14 messagebus: messagebus startup succeeded
Nov 2 11:21:50 swdev14 rhnsd[3245]: Red Hat Network Services Daemon
starting up
.
Nov 2 11:21:50 swdev14 rhnsd: rhnsd startup succeeded
Nov 2 11:21:51 swdev14 kernel: (rc/2112/CPU#2): new 912 us
maximum-latency wake
up.
Nov 2 11:21:51 swdev14 kernel: (ksoftirqd/1/6/CPU#1): new 3147 us
maximum-laten
cy wakeup.
Nov 2 11:21:51 swdev14 kernel: (mingetty/3251/CPU#1): new 3916 us
maximum-laten
cy wakeup.
Nov 2 11:21:51 swdev14 kernel: (init/3253/CPU#2): new 4321 us
maximum-latency w
akeup.
Nov 2 11:21:51 swdev14 kernel: (init/1/CPU#0): new 5332 us
maximum-latency wake
up.
Nov 2 11:21:51 swdev14 kernel: (init/1/CPU#0): new 5819 us
maximum-latency wake
up.
Nov 2 11:21:51 swdev14 kernel: (hotplug/3259/CPU#2): new 6847 us
maximum-latenc
y wakeup.
Nov 2 11:21:51 swdev14 kernel: (hotplug/3274/CPU#2): new 7378 us
maximum-latenc
y wakeup.
Nov 2 11:31:12 swdev14 syslogd 1.4.1: restart.

After the failed reboot a subsequent reboot went fine. This behavior
seems to be pretty much the same for a while now.

My SMP system at home has been running for for 1 hr. 23 mins. so far. No
signs of problems.

kr