Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.6.8
From: K.R. Foley
Date: Tue Nov 02 2004 - 12:57:22 EST
Ingo Molnar wrote:
* Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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
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