CPU oversubscription =?=> spontaneous reboots

[Mike <debian@xxxxxxxxxxxxxxxxxxxxx>]

Has anyone noticed their Xen system spontaneously rebooting itself?

And did that correlate with your overcommitting the vCPUs, by handing out
more than the available number, via the `dom0_max_vcpus` boot param and the
`maxvcpus` domU config param?


I've been experiencing spontaneous reboots of my Xen system lately, and it
seems to correlate with my increasing use of the CPU.  Particularly, it seems
to happen right after I hit the return key to execute a shell command.  The
reboot is sudden: I hear a slight click from the hardware and then I see the
BIOS loading.

So I'm casting about for an answer as to what might cause such a low-level
failure.  Xen or a kernel bug seem like the most likely choices.  The
hardware itself has been otherwise well-behaved in the six months or so that
I've had it running, except for some very early reboots that I attribute
vaguely to "burn-in".

The above matter is drawing my suspicion currently, so to start with I added
`dom0_vcpus_pin` to the boot line and `cpus = "all,^0-3"` to the domU configs
for now.