Recent qemu and timers issue

[Juergen Lock]

In article <c948bb4de85d1b2a340ac63a7c46f6d9 at iem.pw.edu.pl> you write:
>
>Hi all,
>
>When running FreeBSD 8-CURRENT system inside a qemu machine (from the
>latest port by nox at freebsd.org) I have strange timer problems in the
>virtual machine.
>
What is the host running, also current?

>My logs and console are full of messages like this:
>calcru: runtime went backwards from 11248014678717988 usec to 119242 usec
>for pid 60 (ps)                                                            
>        
>calcru: runtime went backwards from 11248014678921829 usec to 2516605 usec
>for pid 60 (ps)                                                            
>calcru: runtime went backwards from 7014844 usec to 6270851 usec for pid 0
>(kernel)
>
>It even happens for some processes to die inside qemu guest.
>
 Is this an smp host?  You could try forcing qemu onto one cpu by
doing like:
	cpuset -l 0 qemu ...

>I tried to use all possible timers using sysctl, where I have:
>TSC(800) HPET(900) ACPI-safe(850) i8254(0) dummy(-1000000)
>None of these helped.
>
 On the host or in the guest?

 You could also try passing `-clock dynticks' to qemu, although I
kinda doubt it would make a difference...
>
>What's more I cannot corelate this with kern.hz value set for the system. I
>tried to set it to the same value as host machine, bigger and smaller one.
>It's not a kqemu issue, happens also with -no-kqemu switch.
>
 Hmm without kqemu the tsc is emulated...  weird.

>I've already posted this issue on freebsd-current some time ago, but
>unfortunately noone showed interest in it..
>(http://docs.freebsd.org/cgi/mid.cgi?3cd67c0d967b2464a4b40bd85582bf88)
>
 Oh, I must have missed that one, sorry.

>I would greatly appreciate any help or a hint - where should I look for
>help on this issue. 
>
 If none of these help you could also try the qemu list:
	http://lists.nongnu.org/mailman/listinfo/qemu-devel
(I think you can still post without being subscribed, altho in that case
it may take a while for the post to get thru.)

 HTH,
	Juergen