[issue1029] Dragonfly under KVM

[Cédric Berger]

Sepherosa Ziehau wrote:
On Sat, Jun 7, 2008 at 7:56 PM, Gary Allan <dragonfly at gallan.co.uk> wrote:
As Freddie says I'm running the QEmu KVM software on Ubuntu x64. DragonFly
is running 32bit with 3.5Gb RAM and 4 CPUs (AMD-Phenom).
I can also trigger SMP DragonFly to lock up during a buildworld on VMWare
Server 1.0.5 (Dual Core, 2Gb RAM) and VirtualBox. I haven't tried the bare
metal but could do so if anyone thinks it would be useful. I'm running HEAD
as of yesterday but 1.12.2 also locks up.
The kernel is GENERIC with "options SMP" and "options APIC_IO" enabled and
I have a box using Phenom 9550 and 2GB ram.  Dfly HEAD runs directly
on the box (no virtual tech involved).  Kernel is configured with SMP
and APIC_IO.  I build world and kernel with -j 8 or -j 16 w/o any
issues.
I've had issues like this with OpenBSD on VMWare a couple year ago.
Actually, VMs emulate "bare metal" systems very well, but they introduce
very unusual timings. So if you've a race that is "to short to be a
serious problem", than that race might well become a real problem on
VMs. To sum up, testing OSes on virtualized environment is a good way
to find hidden/rare bugs :)
Cedric