Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

Mark_H_Johnson
2004-11-01T16:42:53Z

>I've uploaded -V0.6.5 to the usual place:
>
> http://redhat.com/~mingo/realtime-preempt/

I built with this patch and had some problems with the system
locking up.

First attempt:
- booted to single user without problem
- telinit 5 was OK as well
- logged in. After first window popped up, I did
su -
to get root access and the system locked up. No display updates
nor any mouse movement. Entering Alt-SysRq-L displayed
SysRq : Show Regs On All CPUs
and no other messages appeared on the serial console. Attempts
to use other Alt-SysRq keys were ignored, hard reset to reboot.

Second attempt:
- booted to single user without problem
- telinit 5 failed after kudzu timed out (had "detected" a
change due to the serial console)

No messages on serial console after the kudzu timeout. This time
Alt-SysRq-L did work. Also did Alt-SysRq-T and -D and will send
the all the serial console messages separately.

Did notice an odd message during the dump of tasks...
Losing too many ticks!
TSC cannot be used as a timesource.
Possible reasons for this are:
You're running with Speedstep. [almost surely not]
You don't have DMA enabled for your hard disk (see hdparm), [udma4 should
be set at this point]
Incorrect TSC synchronization on an SMP system (see dmesg). [can't look
at that, system is hung]
Falling back to a sane timesource now.

Alas, this "sane timesource" didn't help either, system still
not responding right. Alt-SysRq-S said
SysRq : Emergency Sync
[without any complete messages]
and Alt-SysRq-B did reboot the system.

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